ft  ?[  / 


U.  S.  DEPARTMENT  OF  AGRICULTURE, 

BUREAU  OF  ENTOMOLOGY— BULLETIN  No.  93. 

L.  O.  HOWARD,  Entomologist  and  Chief  of  Bureau. 


THE  SUGAR-CANE  INSECTS  OF  HAWAII. 


BY 


D.  L.  VAN  DIXE, 

Special  Field  Agent. 


Issued  June  15, 


[",  o&N»mT 


U.S.  DEPOSITORY 


WASHINGTON: 

GOVERNMENT    PRINTING    OFFICE. 

1911. 


Bui.  93,  Bureau  of  Entomology,  U.  S.  Dept.  of  Agriculture. 


Plate  I. 


U.  S.  DEPARTMENT  OF  AGRICULTURE, 
BUREAU  OF  ENTOMOLOGY— BULLETIN  No.  93. 

L.  O.  HOWARD,  Entomologist  and  Chief  of  Bureau. 


THE  SUGAR-CANE  INSECTS  OF  HAWAII. 


BY 


D.  L.  VAX  DIXE, 

Special  Field  Agent. 


I— fed  June  15.  1911. 


WASHINGTON: 

GOVERNMENT    PRINTING    OFFICE; 

1911. 


BUREAU  OF  ENTOMOLOGY. 

L.  O.  Howard,  Entomologist  and  Chief  of  Bureau. 

C.  L.  Marlatt,  Entomologist  and  Acting  Chief  in  Absence  of  Chief. 

R.  S.  Clifton,  Executive  Assistant. 

W.  F.  Tastet,  Chief  Clerk. 

F.  H.  Chittenden,  in  charge  of  truck  crop  and  stored  product  insect,  investigations. 

A.  D.  Hopkins,  in  charge  of  forest  insect  investigations. 

W.  D.  Hunter,  in  charge  of  southern  field  crop  insect  investigations. 

F.  M.  Webster,  in  charge  of  cereal  and  forage  insect  investigations. 

A.  L.  Quaintance,  in  charge  of  deciduous  fruit  insect  investigations. 

E.  F.  Phillips,  in  charge  of  bee  culture. 

D.  M.  Rogers,  in  charge  of  preventing  spread  of  moths,  field  work. 
Rolla  P.  Currie,  in  charge  of  editorial  work. 
Mabel  Colcord,  librarian. 

Southern  Field  Crop  Insect  Investigations. 
W.  D.  Hunter,  in  charge. 

W.  D.  Pierce,  J.  D.  Mitchell,  E.  S.  Tucker,  T.  E.  Hollow  ay,  G.  D.  Smith,  E.  A. 
McGregor,  Harry  Pinkus,  W.  A.  Thomas,  Thomas  Lucas,  engaged  in  cotton-boll 
ueevil  investigations. 

F.  C.  Blshopp,  W.  V.  King,  H.  P.  Wood,  G.  N.  Walcott,  engaged  in  tick  investigations. 
A.  C.  Morgan,  G.  A.  Runner,  S.  E.  Crumb,  engaged  in  tobacco  insect  investigations. 
T.  C.  Barber,  C.  E.  Hood,  engaged  in  sugar  cane  and  rice  insect  investigations. 

F.  C.  Pratt,  engaged  in  cactus  insect  investigations. 

D.  L.  Van  Dine,  Wilmon  Newell,  R.  A.  Cooley,  A.  F.  Conradi,  C.  C.  Kbumbhaar, 
collaborators. 
2 


LETTER  OF  TRANSMITTAL. 


U.  S.  Department  of  Agriculture, 

Bureau  of  Entomology, 
Washington,  D.  C,  December  22,  1910. 
Sir:  I  have  the  honor  to  transmit  herewith  for  publication  a  manu- 
script entitled  "The  Sugar-Cane  Insects  of  Hawaii/'  by  Mr.  D.  L. 
Van  Dine,  recently  a  special  agent  of  this  Bureau,  and  for  several 
years  entomologist  of  the  Hawaii  Agricultural  Experiment  Station. 
The  manuscript  includes  a  discussion  of  the  present  status  of  the 
sugar  industry  of  the  Hawaiian  Islands  and  treats  of  the  principal 
insect  enemies  to  this  important  industry,  which  is  rapidly  assuming 
large  proportions  in  our  Southern  States  owing  to  the  increased 
acreage  which  is  being  planted  to  cane.     I  would  recommend  its 
publication  as  Bulletin  No.  93  of  the  Bureau  of  Entomology. 
Respectfully, 

L.  O.  Howard, 

Chief  of  Bureau. 
Hon.  James  Wilson, 

Secretary  of  Agriculture. 


PREFACE. 


The  acreage  devoted  to  sugar-cane  culture  in  the  southern  United 
States  has  increased  rapidly  in  recent  years.  Some  of  the  cotton 
lands,  abandoned  because  of  the  depredations  of  the  cotton  boll 
weevil,  are  being  planted  to  cane.%  New  lands  are  being  planted  to 
the  crop  in  the  Rio  Grande  valley  and  in  the  reclaimed  areas  in  the 
lower  Mississippi  valley.  It  is  stated  that  quite  an  area  of  land 
in  process  of  reclamation  in  the  State  of  Florida  will  be  planted  to 
sugar  cane.  It  is  desirable  that  the  experience  obtained  through 
investigations  of  insects  injurious  to  sugar  cane  in  the  Hawaiian 
Islands  be  placed  at  the  disposal  of  the  planters  in  our  Southern 
States  in  order  that  the  sugar  industry  in  those  States  may  receive 
practical  benefit  therefrom. 

The  Hawaiian  planters  are  well  provided  with  expert  advice  and 
have  at  hand  numerous  reports  dealing  with  the  subject,  which  latter, 
unfortunately,  are  not  available  for  general  distribution.  This  report 
is  written  primarily,  therefore,  for  the  information  of  our  mainland 
planters. 

Acknowledgment  should  be  made  of  the  courtesies  extended  to 
the  writer  by  the  members  of  the  entomological  staff  of  the  Hawaiian 
Sugar  Planters'  Association  Experiment  Station  during  his  return 
visit  to  the  Hawaiian  Islands  in  March  and  April,  1909. 

D.  L.  Van  Dine. 


C  0  N  TEXTS. 


Page. 

Location  and  climate  of  the  Hawaiian  Islands 9 

The  sugar  industry  in  Hawaii 9 

Sugar-cane  insects 11 

The  sugar-cane  leafhopper  (Perkinsiella  saccharicida  Kirk.). 12 

Distribution 12 

Appearance  of  the  leafhopper  in  Hawaiian  cane  fields 12 

Description  of  the  leafhopper 13 

Dispersion  of  the  leafhopper 14 

Life  history  and  habits 15 

Symptoms  of  leafhopper  injury 17 

Character  of  injury  to  the  cane .18 

Extent  of  injury 19 

Factors  responsible  for  the  outbreak  of  1903 20 

The  leafhopper  and  beekeeping 20 

Control  of  the  leafhopper 22 

Direct  measures 22 

Insecticides 22 

Collection  by  nets 22 

Cutting  and  burning  in  the  infested  centers 22 

Stripping  the  leaves 23 

Burning  of  trash  after  harvesting 23 

Indirect  measures 23 

Selection  of  varieties  of  cane  for  planting 23 

Cultural  methods  on  the  plantation 25 

Diversification  of  crops 26 

Control  of  the  rind  disease  of  sugar  cane 26 

Natural  enemies 28 

Species  already  present  in  the  Hawaiian  Islands 28 

Special  introductions 29 

Related  species 34 

The  Hawaiian  sugar-cane  borer  ([Sphenophorus]   Rhabdocnemis  obscurus 

Boisd . ) 35 

General  characteristics 35 

Distribution 36 

Occurrence  in  Hawaii 36 

Life  history  and  habits 37 

Control  measures 39 

Selection  of  varieties  for  planting 39 

Irrigation 39 

Burning  of  trash 39 

Selection  of  noninfested  seed  cane 39 

Picking  and  baiting 39 

Related  species 40 

The  Hawaiian  sugar-cane  leaf-roller  (Omiodes  accepta  Butl.) 41 

Early  history  in  the  Hawaiian  Islands 41 

Control  measures ' 41 

Parasites 41 

7 


8  THE    SXJGAR-CANE    IXSKCTS   OF    HAWAII. 

Sugar-cane  insects — Continued.  rage. 

The  sugar-cane  mealy-bug  (Pseudococcus  calceolaria  Mask.) 43 

Identity 43 

Related  species 43 

Food  plants 43 

Life  history  and  habits 44 

Control 44 

Selection  of  seed  cane 44 

Burning  of  the  trash 44 

Natural  enemies 45 

Miscellaneous  insects  affecting  sugar  cane  in  Hawaii 45 

Rats  injuring  growing  sugar  cane  in  Hawaii 47 

Index 49 


ILLUSTRATIONS. 


PLATES. 

Page. 

Plate   I.  Map  of  the  Hawaiian  Islands Frontispiece. 

II.  The  sugar-cane  leafhopper  (PerKnsiella  saccharicida) .  Fig.  1. — Egg 
chambers  in  midrib  of  cane  leaf,  slightly  enlarged.  Fig.  2. — Eggs, 
greatly  enlarged.  Fig.  3. — First-stage  nymph.  Fig.  4. — Second- 
stage  nymph.  Fig.  5. — Third-stage  nymph.  Fig.  6. — Fourth- 
stage  nymph.     Fig.  7. — Adult  male 16 

III.  The  Hawaiian  sugar-cane  leaf -roller  (Omiodes  accepta).  Fig.  1. — 
Adult  moth.  Figs.  2,  3,  4,  5. — Larva?  and  details.  Fig.  6. — Pupa 
and  details.  Fig.  7. — Apex  of  cremaster,  showing  the  curled 
spines  by  which  the  pupa  is  fastened  to  the  cocoon.  Fig.  8. — 
Cluster  of  4  eggs  in  groove  on  surface  of  leaf.  Fig.  9. — Eggs  more 
highly  enlarged.  Fig.  ]0. — Leaf  spun  together  for  "retreat"  or 
hiding  place  of  caterpillar;  shows  where  caterpillar  has  eaten. 
Fig.  11. — Leaf,  showing  spots  where  a  very  young  caterpillar  has 
eaten,    leaving   one    epidermis   intact,    instead    of   eating   holes 

through  the  leaf 42 

IV.  The  sugar-cane  mealy  bug  (Pseudococcus  calceolaria;).  Fig.  1. — 
Adult  mealy-bugs  clustered  about  the  base  of  young  cane.  Fig. 
2. — Adult  female,  twice  natural  size.  Fig.  3. — A  single  adult 
female,  with  white  mealy-like  covering.  Fig.  4. — Cocoons  of  male 
mealy-bug 44 

TEXT    FIGURES. 

Fig.  1.  The   sugar-cane   leafhopper   (Perlinsiclla   saccharicida):  Adult    female. 

much  enlarged;  ovipositor,  greatly  enlarged 17 

2.  An  apiary  near  a  sugar-cane  field 21 

3.  Yellow  Caledonia  sugar  cane,  a  variety  which  is  replacing  Lahaina  and 

Rose  Bamboo  in  the  Hawaiian  Islands 24 

4.  The  Hawaiian  sugar-cane  borer  ([Sphenophorus]  Rhabdocnemis  obscurus): 

Eggs,  larva?,  pupa,  cocoon,  adult 35 

5.  The  Hawaiian  sugar-cane  borer:  Work  in  sugar  cane 38 


THE  SUGAR-CANE  INSECTS  OF  HAWAII. 


LOCATION  AND  CLIMATE  OF  THE  HAWAIIAN   ISLANDS. 

The  mid-Pacific  Territory  of  Hawaii  (see  Plate  I)  is  situated  2,100 
miles  to  the  southwest  from  San  Francisco,  the  California  coast 
being  the  nearest  continental  area.  The  islands  are  separated  by 
channels  varying  from  20  to  58  miles  in  width.  The  8  inhabit- 
able islands,  Hawaii,  Maui,  Oahu,  Kauai,  Molokai,  Lanai,  Kahoolawe, 
and  Niihau,  lie  between  18°  54'  and  22°  15'  north  latitude;  that  is, 
the  northern  hmit  of  the  islands  is  just  within  the  Tropics.  The 
climate  of  the  entire  group  is,  however,  only  subtropical,  due  largely 
to  the  prevailing  northeasterly  trade  winds,  the  cool  ocean  currents 
from  the  north,  and  the  relatively  low  humidity.  The  temperature 
varies  according  to  the  altitude  and  the  location  of  the  land  as 
regards  the  higher  mountains.  The  formation  of  the  islands  is  of 
recent  volcanic  nature,  with  the  exception  of  the  low-lying  coastal 
plains,  winch  are  of  coral  origin. 

The  annual  maximum  temperature  ranges  from  88°  to  90°  F., 
while  the  annual  minimum  temperature  recorded  ranges  from  52°  to 
58°  F.  A  temperature  of  29°  F.  has  been  recorded  at  an  altitude  of 
6,685  feet,  and  freezing  temperatures  are  of  frequent  occurrence  at 
these  high  altitudes.  The  rainfall  varies  in  amount  with  the  locality. 
Places  within  a  few  miles  of  each  other  are  known  to  differ  more  than 
100  inches  in  average  annual  rainfall.  The  sides  of  the  islands 
exposed  to  the  northeast  trade  winds  have  abundant  rains,  while  the 
opposite  sides  have  little  and  some  localities  hardly  any. 

The  soils  of  the  islands  are  exceedingly  fertile  and  when  properly 
cultivated  yield  abundant  crops.' 

THE  SUGAR  INDUSTRY  IN  HAWAII. 

The  production  of  sugar  is  the  leading  industry  in  the  Hawaiian 
Islands.  Sugar  cane  is  grown  on  four  of  the  islands.  The  island  of 
Hawaii  has  the  largest  acreage  devoted  to  cane,  Oahu,  Maui,  and 
Kauai  coming  next  in  importance  in  the  order  named.  There  are 
more  than  200,000  acres  planted  to  cane  in  the  islands.  In  1908 
521,000  tons  of  raw  sugar  were  produced,  having  a  value  of  more 
than  $40,000,000.  The  average  yield  of  sugar  per  acre  is  44  tons. 
83327°— Bull.  93—11 2  9 


10  THE    SUGAR-CANE   INSECTS   OF    HAWAII. 

The  plant  crop  is  taken  off  20  to  22  months  from  the  time  of  plant- 
ing, and  the  first  ratoon  or  stubble  is  harvested  18  to  20  months 
later.  The  second  ratoon  usually  goes  18  months  again  before 
it  is  ground.  Sometimes  a  "short  ratoon"  crop  is  made,  in  which 
case  the  cane  runs  about  14  months.  The  time  given  for  growth 
depends  on  the  maturity  of  the  cane,  which  in  turn  is  governed  by 
the  location  and  altitude  of  the  land.  To  some  extent  also  the  time 
of  harvest  is  governed  by  the  labor  supply,  factory  conveniences  for 
taking  off  and  grinding  the  crop,  and  the  need  of  land  for  planting. 

The  sugar  industry  in  Hawaii  was  placed  on  a  basis  to  insure  its 
becoming  the  leading  industry  by  the  reciprocity  treaty  of  1876 
between  the  United  States  and  the  Hawaiian  Government,  the  latter 
at  that  time  being  an  independent  monarchy.  The  effect  of  this 
treaty  in  removing  the  duty  on  raw  sugar  exported  to  the  United 
States  was  to  increase  American  influence  in  the  islands  and  to 
strengthen  the  commercial  relations  between  the  two  countries.  A 
second  great  factor  m  the  development  of  the  sugar  industry  was  the 
annexation  of  the  islands  as  a  Territory  of  the  United  States  by  an 
act  of  Congress  passed  July  7,  1898,  by  mutual  agreement  between 
the  two  countries,  Hawaii  at  that  time  having  overthrown  the  mon- 
archy and  become  a  republic.  Annexation  insured  a  free  and  pro- 
tected market  to  the  sugar  output  of  the  islands  and  gave  confidence 
for  the  investment  of  capital.  This  is  of  prime  importance,  as  the 
production  of  sugar  in  the  islands  is  on  a  corporation  basis  and  any 
disturbance  in  the  market  is  felt  at  once  by  every  plantation  in  the 
Territory. 

Fundamental  factors  that  have  attended  the  development  of  the 
sugar  industry  are  the  equable  climate  of  the  islands,  the  natural 
productiveness  of  the  soil,  the  resources  of  water  for  irrigation  pur- 
poses, and  the  immunity  from  the  more  serious  depredations  by 
insects  and  diseases  that  retard  the  development  of  agricultural 
resources  in  less  fortunate  parts  of  the  world.  Further,  there  is  to 
be  found  in  Hawaii  a  class  of  progressive  business  men  who  have 
developed  immense  irrigation  schemes,  made  use  of  the  most  modern 
agricultural  and  factory  machinery,  inaugurated  advanced  methods 
of  cultivation,  fertilization,  and  irrigation,  and  united  their  interests 
in  a  cooperative  association. 

This  organization,  the  Hawaiian  Sugar  Planters'  Association,  has, 
since  April,  1895,  maintained  a  private  experiment  station,  where 
important  researches  have  been  made  and  valuable  results  obtained. 
The  work  has  applied  to  varieties  and  seedhngs,  propagation,  culti- 
vation, irrigation,  the  use  of  fertihzers,  and  the  manufacture  of 
sugar.  These  investigations,  together  with  the  perfection  of  factory 
methods  and  field  machinery,  have  brought  the  sugar  industry  of 
the  islands  to  the  high  standard  it  holds  among  the  sugar-producing 
countries  of  the  world. 


THE    SUGAR-CANE   LEAFHOPPER  11 

SUGAR-CANE  INSECTS. 

The  advent  of  a  serious  pest  into  the  Hawaiian  sugar-cane  fields, 
the  sugar-cane  leafhopper  {Perkinsiella  saccharicida  Kirk.),  between 
1900  and  1902  and  the  widespread  injury  of  this  insect  throughout 
the  sugar-cane  districts  in  1903  led  to  the  establishment  of  an  ento- 
mological division  in  the  Sugar  Planters'  Experiment  Station  in 
September,  1904.  In  tins  division  detailed  studies  have  been  made 
of  the  species  of  insects  occurring  in  the  Hawaiian  cane  fields,  the 
investigations  relating  particularly  to  the  leafhopper  and  its  natural 
enemies. 

Koebele  a  has  earlier  discussed  the  sugar-cane  insects.  Up  to  the 
time  of  the  leafhopper  invasion  the  sugar-cane  borer  ([Sphenophorus] 
RJiabdocnemis  obscurus  Boisd.)  was  the  most  injurious  species.  The 
sugar-cane  aphis  (ApMs  saccJiari  Zehntner),  the  sugar-cane  mealy-bug 
(Pseudococcus  calceolarise  Maskell),  the  leaf -roller  (Omiodes  accepta 
Butler),  cutworms,  and  certain  other  pests  occurred  locally,  but  up 
to  this  time  no  detailed  study  of  their  injury  had  been  made. 

An  insect  enemy  of  sugar  cane  has  exceptional  advantages  for 
development  in  the  Hawaiian  Islands.  Approximately  only  one- 
half  the  total  area  is  harvested  at  any  one  time.  Thus  the  great 
extent  of  the  plant  gives  an  abundant  supply  of  food,  while  the  system 
of  cropping  provides  a  continuous  supply.  These  conditions, 
together  with  the  even  climate,  favor  the  uninterrupted  breeding 
of  any  enemy  of  the  plant.  A  further  factor  in  the  undue  increase 
of  the  cane-feeding  insects  is  the  impetus  to  development  arising 
from  the  absence  of  the  special  parasitic  and  predaceous  enemies 
of  the  plant-feeding  species.  The  absence  of  natural  enemies  is 
understood  when  it  is  known  that  the  islands  are  isolated  from  all 
continental  areas  and  that  the  economic  plants  are  introduced  forms 
for  which  the  native  flora  has  made  way,  carrying  with  it  the  endemic 
species  of  insects,  while  the  insect  enemies  of  a  cultivated  plant  are 
of  foreign  origin,  introduced  into  the  islands  with  their  host  plant 
but  without  their  natural  enemies.  These  very  facts,  together  with 
the  almost  total  absence  of  secondary  parasites  as  a  group  and  the 
opportunity  of  eliminating  them  when  introductions  are  made, 
furnish  ideal  conditions  for  the  introduction  and  establishment  of 
special  parasitic  insects.  The  greatest  factor  in  the  successful 
establishment  of  a  special  parasite  is  the  absence  of  the  secondary 
parasites  of  which  it  is  the  host.  One  can  understand  why  emphasis 
has  been  placed  on  the  use  of  natural  enemies  in  the  control  of 
injurious  species  in  Hawaii  and  why  also  greater  success  has  been 

a  Hawaiian  Planters'  Monthly,  vol.  15,  no.  12,  pp.  590-598,  December,  1896;  vol. 
17,  nos.  5  and  6,  pp.  208-219  and  258-269,  May  and  June,  1898;  vol.  18,  no.  12,  pp. 
576-578,  December,  1899;  vol.  19,  no.  11,  pp.  519-524,  November,  1900. 


12  THE    BUGAB-CANE    [NSECTS    OF    HAWAII. 

attained  in  Hawaii  than  in  continental  regions  where  investigations 
of  this  character  are  under  way.  From  the  above  remarks  it  is 
apparent  that  the  entomologists  of  the  Hawaiian  Sugar  Planters' 
Experiment  Station  are  justified  in  placing  emphasis  on  this  phase 
of  insect  control.  Indeed,  their  work  has  been  almost  entirely 
along  this  line. 

THE   SUGAR-CANE   LEAFHOPPER. 

(Perkinsiella  saccharicida  Kirk.) 
DISTRIBUTION. 

The  Hawaiian  sugar-cane  leaf  hopper  (Perkinsiella  saccltaricida 
Kirkaldy)  was  introduced  into  the  islands  some  time  prior  to  1900 
from  Queensland,  Australia.  The  species  occurs  throughout  the. 
sugar-cane  areas  both  in  Australia  and  in  Hawaii  and  has  been 
recorded  from  Java.a 

APPEARANCE    OF    THE    LEAFHOPPER    IX    HAWAIIAN    CANE    FIELDS. 

The  first  appearance  of  the  leafhopper  in  Hawaii  is  recorded 
by  Mr.  Albert  Koebele  in  January,  1902.6  Koebele  notes  the  species 
under  the  heading  "Leafhopper  (Fulgoridae),"  the  species  at  that 
time  not  having  been  described.  Regarding  its  appearance  Mr. 
Koebele  says: 

According  to  Mr.  Clark  a  small  homopterous  insect  appeared  upon  the  BUgar  cane 
at  the  experimental  station  some  twelve  months  since,  affecting  the  Demerara  and 
Rose  Bamboo  plants.  Its  presence  is  easily  seen  by  the  black  and  dirty  appearance 
of  the  leaves  and  more  or  less  red  midribs. 

The  insect  lives  in  company  with  its  larva  in  large  numbers  behind  leaf  sheaths, 
which  it  punctures  to  imbibe  the  sap  of  the  plant.  When  mature  it  is  exceedingly 
active  in  its  habits,  springing  with  suddenness  from  its  resting  place  at  the  least  dis- 
turbance. The  eggs  are  oviposited  into  the  midrib  over  a  large  extent,  most  numerous 
near  the  base,  in  groups  of  about  from  four  to  seven,  and  large  quantities  are  often 
present  in  a  single  leaf.  The  surroundings  of  the  sting  become  red  and  in  advanced 
stages  the  whole  of  the  midrib  becomes  more  or  less  of  this  color  and  brownish  red. 

That  the  species  caused  little  alarm  at  this  time  is  indicated  by 
Mr.  Koebele's  further  statement  in  this  same  article.     He  says: 

Should  this  insect  become  numerous  on  any  plantation,  they  could  be  kept  in 
check  by  careful  and  repeated  stripping  and  burning,  immediately  after,  of  the  leaves 
containing  the  eggs.  I  do  not  anticipate  any  serious  results  from  the  above  insect, 
which  may  have  been  present  upon  the  island  for  many  years. 

In  May,  1902,  Dr.  R.  C.  L.  Perkins  under  the  title  "Leafhoppers 

(Fulgoridae),"  in  a  report  to  Mr.  C.  F.  Eckart,  director  of  the  Hawaiian 

a  Kirkaldy,  G.  W. — A  note  on  certain  widely  distributed  leafhoppers.  <Science, 
vol.  26,  no.  659,  p.  216,  1907. 

b  Koebele,  A. — Report  of  the  committee  on  diseases  of  cane.  <Hawaiian  Planters' 
Monthly,  vol.  21,  no.  1,  pp.  20-26,  January,  1902. 


THE    SUGAR-CANE    LEAFHOPPER.  13 

Sugar  Planters'  Experiment  Station,  mentions  the  doubtful  origin 
and  identity  of  the  species. a  Doctor  Perkins  agajn  records  the  insect 
under  the  heading  "The  leaf-hopper  of  the  cane"  in  December  of 
the  same  year  and  says:  "This  small  insect  is  highly  injurious  to 
cane  and  its  destructiveness  threatens  to  exceed  that  of  the  cane 
borer  beetle."6 

In  response  to  repeated  requests  made  to  the  department  the 
writer  was  detailed  early  in  May,  1903,  to  make  a  report  on  the 
pest.  On  May  11,  1903,  specimens  were  forwarded  by  the  writer 
to  Dr.  L.  O.  Howard,  Chief  of  the  Bureau  of  Entomology,  Wash- 
ington, D.  C.  Under  date  of  June  1,  1903,  Doctor  Howard  replied 
that  the  species  was  new  to  science  and  that  there  was  in  press  a 
description  of  the  insect  under  the  name  Perkinsiella  saccharicida 
by  Mr.  G.  W.  Kirkaldy  of  the  British  Museum. 

DESCRIPTION    OF   THE    LEAFHOPPER. 

The  species  was  described  by  Mr.  G.  W.  Kirkaldy  in  1903  and  rep- 
resents a  new  genus  which  was  named  after  Dr.  R.  C.  L.  Perkins. 
The  description  of  the  genus  and  species  is  taken  from  Mr.  Kirkaldy's 
article  in  The  Entomologist,  London,  for  July,  1903,  pages  179-180, 
and  is  as  follows : 

Perkinsiella,  gen.  no  v. 

Closely  allied  to  Arseopus  Spinola,  but  distinguished  by  the  first  segment  of  the 
antennae  being  distinctly  shorter  than  the  second;  distinguished  from  Dicranotropis 
Fieber,  to  which  it  bears  some  resemblance,  by  the  form  of  the  frons,  and  by  the 
flattened  apically  dilated  first  segment  of  the  antennae.  Type,  P .  saccharicida  Kirkaldy. 
Second  segment  of  antennal  peduncle  about  one-half  longer  than  the  first;  flagel- 
lum  about  one-third  longer  than  the  entire  peduncle,  first  peduncular  segment  much 
wider  at  apex  than  basally,  flattened  and  explanate;  second  segment  nearly  as  wide 
at  base  as  the  apex  of  the  first  segment  [in  Arseopus  it  is  much  narrower,  while  the  first 
segment  is  more  parallel-sided].  Exterior  longitudinal  nervure  of  corium  forked  near 
the  base,  and  its  exterior  branch  forked  near  its  middle;  interior  longitudinal  nervure 
forked  near  the  apex.  Membrane  with  six  nervures,  the  fourth  (commencing  inwardly) 
forked;  the  first  area  has  an  incomplete  nervure  reaching  only  to  the  middle.  Other 
characters  as  in  Arseopus. 

P.  saccharicida,  sp.  nov. 

Long-it'inged  form  $  9  • — Tegmina  elongate,  narrow,  extending  far  beyond  apex  of 
abdomen,  interior  half  of  clavus  and  corium  more  or  less  faintly  smoky,  a  long  dark 
smoky  stripe  on  middle  of  membrane,  three  or  four  of  nervures  of  the  latter  smoky  at 
apex. 

Short-winged  form,  9  • — Tegmina  reaching  only  to  base  of  fifth  segment,  costa  more 
arched,  apex  more  rounded,  neuration  similar  but  shortened.  Tegmina  hyaline, 
colourless;  nervures  pale  testaceous  brownish,  with  blackish  brown  non-piligerous 
dots  (in  both  forms). 

^Eckart,  C.  F. — Precautions  to  be  observed  with  regard  to  cane  importations. 
<Report  to  Hawaiian  Sugar  Planters'  Association,  May  9,  1902,  p.  5. 

&  Perkins,  R.  C.  L. — Notes  on  the  insects  injurious  to  cane  in  the  Hawaiian  Islands. 
< Hawaiian  Planters'  Monthly,  vol.  21,  no.  12,  pp.  593-596,  December,  1902. 


14  THE    SUGAR-CANE   INSECTS   OF    HAWAII. 

$  .  Pallid  yellowish  testaceous.  Abdomen  above  and  beneath  black,  apical  mar- 
gins and  laterally  more  or  less  widely  pallid.  Apical  half  of  first  segment  and  carinate 
edges  of  second  segment  of  antenna?,  flagellum,  basal  half  of  frons  (except  the  pustules  | 
and  a  cloudy  transverse  band  near  the  apical  margin  of  the  same,  longitudinal  stripes 
on  femora,  coxa?  spotted  or  banded  near  the  base,  a  large  spot  on  each  pleuron,  anterior 
and  intermediate  tibia?  with  two  or  three  annulations,  apical  segment  of  tarsi,  etc., 
blackish  or  brownish.  First  genital  segment  large,  deeply  acute-angularly  emarginate 
above. 

9  •  Like  the  male,  but  abdomen  above  and  beneath  stramineous,  irregularly  speckled 
with  brownish.  Ovipositor,  etc.,  blackish.  Sheath  not  extending  apically  so  far  as 
the  "scheidenpolster.  "  Long.  $  <%\\  mill.;  to  apex  of  elytra  in  long-winged  form, 
6$  mill. 

DISPERSION    OF    THE    LEAFHOPPER. 

The  spread  of  the  insect  over  the  cane  districts  of  the  Hawaiian 
Islands  was  apparently  very  rapid,  although  it  had  undoubtedly 
occurred  in  the  fields  unnoticed  by  the  planters  for  several  years.  By 
February,  1903,  the  species  became  generally  abundant  throughout 
the  cane  fields  of  the  entire  Hawaiian  Territory. 

The  main  factor  in- the  distribution  of  the  pest  is  the  habit  of  the 
female  of  depositing  her  eggs  beneath  the  epidermis  of  the  internodes 
of  the  cane  stalk.  It  seems  probable  that  the  pest  was  introduced 
into  the  islands  and  to  a  great  extent  distributed  over  the  cane 
districts  in  seed  cane.  In  local  distribution  other  factors  present 
themselves.  The  leafhopper  is  an  insect  readily  attracted  by  light 
at  night,  as  its  presence  about  lamps  in  the  factories  and  homes  on 
the  plantations  testifies.  Passengers  and  steamship  officers  of  the 
interisland  steamers  have  frequently  stated  to  the  writer  on  inquiry 
that  in  many  instances,  especially  at  night,  great  numbers  of  the 
insects  have  come  aboard  in  certain  ports  or  when  offshore  from 
certain  plantation  districts.  .  These  adults  have  undoubtedly  traveled 
in  this -manner  from  one  locality  to  another  so  that  an  uninfested  dis- 
trict might  easily  have  become  infested  by  adults  flying  ashore  from  a 
passing  steamer  previously  infested  while  stopping  at  or  passing  by 
an  infested  locality.  Railway  trains  have  been  equally  active  in  the 
spread  of  the  insect  on  land. 

Another  mode  of  distribution,  during  the  general  outbreak  of  1903, 
under  conditions  of  heavy  infestation,  was  the  migration  of  the  pest 
from  one  locality  to  another  during  the  daytime.  These  migrations 
were  observed  by  many  of  the  planters.  The  manager  of  one  planta- 
tion in  the  Hamakua  district  of  the  island  of  Hawaii  stated  to  the 
writer  that  in  the  early  evening  of  April  26,  1903,  the  atmosphere  was 
"thick  with  hoppers"  for  a  distance  of  2  miles  and  that  the  "hop- 
pers" were  traveling  with  the  prevailing  wind,  about  southwest. 
Similar  migrations,  described  by  the  observers  as  "clouds,"  were 
mentioned  by  other  managers. 


THE    SUGAR-CANE   LEAFHOPPER.  15 

LIFE    HISTORY   AND   HABITS. 

The  writer  spent  two  months  in  the  cane  fields  during  the  outbreak 
and  in  the  early  part  of  July,  1903,  presented  a  report  to  the  Hawaiian 
Sugar  Planters'  Association  on  the  occurrence  and  injury  of  the 
species.  Later  an  account  of  these  investigations  was  published, 
from  which  a  part  of  the  information  on  the  leafhopper  presented 
herewith  is  taken.0 

''Leafhopper"  is  a  popular  term  applied  to  a  certain  group  of 
plant-feeding  insects  of  the  order  Hemiptera.  The  family  Fulgo- 
ridse,  to  which  the  Hawaiian  sugar-cane  leafhopper  belongs,  is 
included  in  this  group.  Common  characteristics  of  these  insects 
are  their  peculiar  habit  of  springing  or  jumping  when  disturbed; 
their  feeding  upon  plants  by  sucking  from  the  tissue  the  plant  juice 
or  sap  through  a  beak  or  proboscis,  a  piercing  organ  by  means  of 
which  they  puncture  the  epidermal  layer  of  the  plant ;  their  incom- 
plete development  (that  is,  the  young  upon  hatching  from  the  eggs 
resembles  the  adult,  except  that  it  is  smaller  in  size,  wingless,  and 
sexually  immature  and  by  a  gradual  process  of  development  acquires 
the  characteristics  of  the  adult) ;  and  the  fact  that  their  eggs  are 
deposited  in  the  same  plant  upon  which  the  young  and  adult  appear 
and  feed. 

The  eggs  of  the  sugar-cane  leafhopper  (Plate  II,  figs.  1,  2)  are 
deposited  beneath  the  epidermis  of  the  cane  plant  in  situations 
along  the  midrib  of  the  leaves,  in  the  internodes  of  the  stalk,  or,  in 
the  case  of  young  unstripped  cane,  in  the  leaf  sheath  of  the  lower 
leaves.  When  deposited  in  the  leaves,  the  eggs  are  inserted  from 
either  side,  but  usually  from  the  inside,  the  greater  number  being 
in  the  larger  portion  of  the  midrib  down  toward  the  leaf  sheath. 
The  place  of  incision  is  indicated  at  first  by  a  whitish  spot,  this  being  a 
waxy  covering  over  the  opening.  The  female  accomplishes  the  process 
of  oviposition  by  puncturing  the  leaf  or  stem  with  her  ovipositor, 
which  organ  (fig.  1,  b)  is  plainly  visible  on  the  lower  side  of  the  abdo- 
men, attached  to  the  body  at  the  center  behind  the  last  pair  of  legs 
and  extending  backward  along  the  median  line  of  the  abdomen, 
reaching  nearly  to  the  end.  By  the  aid  of  this  structure  the  female 
pierces  the  epidermis  of  the  cane  stalk  and  through  the  one  opening 
forms  a  cavity  or  chamber  to  receive  the  eggs.  The  number  of 
eggs  deposited  in  each  cavity  varies,  the  writer  finding  the  average 
to  be  between  four  and  six.  That  a  single  female  is  responsible  for 
many  of  these  clusters  has  been  verified  by  the  writer  by  observation. 
As  the  growth  of  the  cane  continues  and  the  new  leaves  unfold 
toward  the  top  of  the  plant,  the  infested  leaves  naturally  occupy 

a  Van  Dixe.  D.  L. — A  sugar-cane  leaf-hopper  in  Hawaii,  Perkinsiella  saccharicida. 
<Hawaii  Agr.  Exp.  Sta.,  Honolulu,  Bui.  5,  pp.  29,  figs.  8.  1904. 


16  THE    SUGAR-CANE    INSECTS    OF    HAWAII. 

the  lower  position  on  the  stalk.  The  leafhopper,  during  a  heavy 
infestation,  will  continue  to  puncture  the  midribs  of  the  leaves  as 
rapidly  as  the  leaves  unfold.  The  older  egg  chambers  of  the  lower 
leaves  are  distinguished  from  the  newly  formed  chambers  of  the 
upper  leaves  by  a  reddish  discoloration. 

Under  laboratory  conditions  the  writer  found  that  the  eggs 
deposited  in  cane  growing  in  rearing  cages  hatched  two  weeks  there- 
after. The  period  of  development  of  the  young  to  the  adult  required 
34  additional  days,  making  the  life  cycle  48  days  in  length. 

The  length  of  the  egg  stage,  under  certain  conditions,  is  much 
longer  than  the  time  given  above.  Mr.  C.  F.  Eckart,  director  of 
the  Hawaiian  Sugar  Planters'  Experiment  Station,  records  that  hatch- 
ing continued  for  38  days  from  cane  cuttings  infested  with  eggs  of 
the  leaf  hopper. a 

The  fact  that  the  eggs  will  hatch  from  cane  cuttings  during  a 
period  of  at  least  38  days  is  a  very  important  point  to  bear  in  mind 
in  the  shipping  of  infested  cane  from  one  locality  or  country  to 
another.  Since  practically  the  only  means  by  which  the  Hawaiian 
leafhopper  could  be  introduced  into  the  cane  fields  of  the  Southern 
States  is  by  the  shipment  of  seed  cane  from  New  South  Wales, 
Queensland,  Java,  or  Hawaii  to  this  country,  the  writer  would 
emphasize  the  necessity  of  having  all  introductions  made  through 
officials  engaged  in  sugar-cane  investigations. 

On  issuing  from  the  cavity,  or  chamber,  the  young,  newly  hatched 
leafhoppers  appear  at  first  small,  slim,  wingless  n3rmphs,  almost 
transparent.  During  the  process  of  hatching  or  emerging  from 
the  egg  chamber  the  insects  slowly  work  their  way  head  first  to  the 
surface  of  the  leaf  or  stalk.  The  writer  found,  by  timing  the  opera- 
tion, that  from  8  to  15  minutes  were  required,  during  which  time 
the  nymphs  rest  occasionally  to  unfold  and  dry  their  legs.  When 
they  become  detached  from  their  egg-cases  and  have  emerged  to 
the  surface,  they  are  at  once  active  and  scatter  over  the  plant  to 
feed,  congregating  at  first  down  within  the  sheaths  of  the  upper 
leaves.  In  a  few  hours  the  body  becomes  shortened  and  the  outer 
covering,  on  exposure  to  the  air,  becomes  darker  in  color.  The  habit 
of  the  very  young  in  secluding  themselves  within  the  lower  sheaths 
of  the  leaves  renders  them  quite  inconspicuous  unless  especially 
sought  for.  They  may  become  very  abundant  and  still  remain  unde- 
tected by  an  ordinary  observer  until  the  result  of  their  feeding 
becomes  apparent.     (See  nymphs,  Plate  II,  figs.  3-6.) 

Ordinarily  when  disturbed  the  adult  leafhopper  does  not  fly  but 
moves  off  in  an  odd,  sidewise  fashion  to  another  part  of  the  leaf,  or 
springs  suddenly  to  another  portion  of  the  plant.  (See  adults, 
Plate  II,  fig.  7,  and  text  fig.  1.) 

°  Eckart,  C.  F. — Report  of  the  Hawaiian  Sugar  Planters'  Association  Experiment 
Station  for  1903,  Honolulu,  1904,  pp.  78-79. 


Bui.  93,  Bureau  of  Entomology,  U.  S.  Dept.  of  Agriculture. 


Plate  II. 


The  Suqar-Cane  Leafhopper  (Perkinsiella  saccharicida). 

Fig.  1. — Egg  chambers  in  midrib  of  cane  leaf,  slightly  enlarged.  Fig.  2. — Eggs,  greatly  enlarged. 
Fig.  3.— First-stage  nymph.  Fig.  ■!.— Second-stage  nymph.  Fig.  5.— Third-stage  nymph.  Fig.  6.— 
Fourth-stage  nymph.    Fig.  7.— Adult  male.     (After  Kirkaldy.) 


THE    SUGAR-CANE    LEAFHOPPER. 


17 


SYMPTOMS    OF    LEAFHOPPER    INJURY. 

The  presence  of  the  pest  on  the  plantations  was  noticed  first  by 
the  appearance  of  a  sooty  black  covering  on  the  lower  leaves  of  the 
cane  plant.  This  black  covering  became  known  as  smut.  It  is  a 
fungous  growth  and  finds  a  medium  for  development  in  the  trans- 
parent, sticky  fluid  secreted  by  the  leaf  hoppers  during  their  feeding 
on  the  plant.     This  secretion  is  commonly  known  as  honeydew. 

The  black  smut  or  fungous  growth  in  the  honeydew  secretion  of 
the  leafhopper  and  the  red  discoloration  about  the  openings  to  the 
egs;  chambers  in  the  midribs  of  the  leaves  are  the  most  pronounced 
svmptoms  of  the  work  of  the 
leafhopper  on  cane. 

In  the  case  of  heavy  infesta- 
tion a  further  result  is  the 
appearance  of  the  plant  as  a 
whole.  The  leaves  on  winch  the 
insects  have  been  feeding  de- 
velop a  yellowish  appearance, 
and  as  the  work  of  the  insects 
progresses  they  become  dried 
and  resemble  the  fully  matured 
lower  leaves  of  the  plant.  This 
premature  death  of  the  leaves 
is  due  to  the  excessive  amount 
of  juice  extracted  for  food.  As 
long  as  the  cane  plant  is  able  to 
produce  new  leaves  its  life  is 
not  actually  in  danger,  the  in- 
jury being  a  check  to  the  growth 
and  indicated  by  the  small, 
shortened  joints  in  the  stalk. 
Leaves  thus  prematurely  rip- 
ened do  not  drop  away  from 
the  stalk  at  the  junction  of  the  sheath,  as  is  the  case  under  normal 
conditions,  but  break  and  hang  down  at  the  junction  of  the  leaf  to 
the  sheath,  leaving  the  sheath  still  wrapped  about  the  stalk.  Leaves 
in  such  a  condition  remain  green  for  some  time,  attached  to  the 
sheath  by  the  midrib,  and  an  attempt  to  strip  the  cane  results  in 
leaving  the  sheaths  still  adhering  to  the  stalk  and  wrapped  about  it. 

In  the  last  stages  of  an  attack,  when  the  plant  is  actually  overcome 

by  the  pest,  the  young  unfolded  leaves  at  the  top  do  not  appear 

to  have  the  vitality  to  unfold  and  the  ''bud"  gradually  dies  out.     At 

this  stage  the  normal  growth  of  the  plant  ceases.     Many  plants  in 

83327°— Bull.  93—11 3 


Fig.  1.— The  sugar-cane  leafhopper  (Perkinsiella  sac- 
charicida):  a,  Adult  female,  much  enlarged;  b, 
ovipositor,  greatly  enlarged.    (After  Kirkaldy.) 


18  THE    SUGAR-CANE   INSECTS   OF    HAWAII. 

such  a  condition  will  then  throw  out  sprouts  from  the  eyes.  This  is 
a  serious  circumstance,  since  the  growth  of  the  sprouts  is  supported 
by  the  stalk,  and  unless  the  cane  is  soon  cut  and  ground  the  stalk  is 
rendered  worthless. 

CHARACTER    OF    INJURY    TO    THE    CANE. 

The  first  injury  to  the  cane  plant  by  the  leafhopper  occurs  through 
the  piercing  of  the  epidermal  layer  by  the  ovipositor  (fig.  1,  b)  of  the 
female  and  the  later  rupturing  of  the  tissue  of  the  plant  on  the  hatch- 
ing of  the  young.  This  injury  to  the  tissue  in  itself  is  not  serious, 
but  the  many  openings  in  the  leaves  and  stalks  allow  excessive 
evaporation  to  occur.  Through  these  wounds  various  diseases  may 
also  gain  entrance  to  the  tissues  of  the  plant,  carried  thereto  by  the 
leafhoppers  themselves  in  flying  from  infested  to  noninfested  plants, 
or  by  other  insects,  particularly  certain  flies,  which  frequent  the 
cane  plant. 

The  most  serious  injury  to  the  plant  is  the  drain  upon  its  vitality 
caused  by  the  young  leafhoppers  in  feeding.  The  structure  of  the 
mouth  parts  of  the  leafhopper  has  been  mentioned;  that  is,  a  piercing 
organ,  which  is  inserted  through  the  outer  covering  of  the  tissue,  by 
means  of  which  the  insect  sucks  the  juice  or  sap  from  within.  The 
amount  extracted  in  this  manner  by  any  particular  individual  is  small 
and  of  little  consequence,  but  the  result  of  a  myriad  of  individuals  work- 
ing constantly  in  this  manner  upon  a  plant  is  readily  conceived  to  be 
serious  in  its  consequences.  The  leafhopper  in  feeding  upon  the 
cane  plant  extracts  therefrom  an  amount  of  juice  greatly  in  excess 
of  its  own  needs  for  development.  This  excess  is  excreted  from  the 
body  of  the  insect  upon  the  cane  plant  in  the  form  of  a  sweet,  sticky 
substance,  known  as  hone3rdew.  It  is  in  tins  substance  that  the 
black  smut  develops. 

The  sooty  covering  or  smut  of  the  leaves  referred  to  is  a  super- 
ficial fungus  winch  bears  a  close  resemblance  to  the  fungi  of  the  genus 
Sphaeronema.  The  writer  was  informed  by  Dr.  A.  F.  Woods,  at  that 
time  Pathologist  of  the  United  States  Department  of  Agriculture, 
that  this  fungus  may  be  responsible  for  the  d}Tiig  back  of  canes 
which  followed  heavy  leafhopper  infestation.  It  is  believed,  how- 
ever, that  in  the  cane  the  smut  affects  the  plant  only  by  preventing 
the  assimilation  of  the  elements  taken  up  by  the  plant  from  the  soil 
as  food,  in  cutting  off  the  rays  of  direct  sunlight,  and  also  in  closing 
the  stomata  of  the  leaves,  preventing  the  entrance  and  escape  of 
carbon  dioxid  and  oxygen,  respectively.  In  damp  localities  another 
fungus  was  taken  in  company  with  the  smut,  arid  was  determined 
by  Dr.  Woods  as  a  species  of  the  genus  Hypochnus.  The  resulting 
injury  to  the  plant  from  the  leafhopper  attack  is  also  complicated  by 


THE    SUGAR-CANE   LEAFHOPPER.  19 

the  presence  of  the  pineapple  disease  of  sugar  cane  (TMelaviopsis 
ethaceiicus)  and  the  rind  disease  (Mela neon him  sacchari).  The  latter 
species,  it  is  believed,  gains  entrance  to  the  tissue  of  the  plant  through 
the  wounds  made  by  the  leafhopper. 

EXTENT    OF    INJURY. 

It  was  estimated  that  the  leafhopper  caused  a  loss  of  S3, 000, 000  to 
the  planters  of  Hawaii  during  1903  and  1904.a  In  the  writer's 
opinion  this  loss  can  not  be  attributed  entirely  to  the  leafhopper 
injury.  Other  species  of  insects  and  certain  diseases  were  implicated. 
The  leafhopper  was  directly  responsible  for  the  larger  percentage  of 
loss  and  indirectly  responsible  for  the  unusual  development  of  cer- 
tain diseases. 

In  speakhig  of  the  rind  disease  of  sugar  cane  in  Hawaii  in  1907 
Mr.  L.  Lewton-Brain  says:6 

To  bring  before  you  the  actual  extent  of  the  loss  that  the  rind  disease  is  now  causing 
in  your  cane  fields.  I  take  the  following  fact  obtained  by  Doctor  Cobb  from  actual 
counts  in  the  field.  In  one  case  the  cane  left  on  the  ground  represented  about  one 
ton  of  sugar  to  the  acre.  That  is  to  say.  that  if  the  cane  left  on  the  field  had  been 
sound  cane  that  portion  of  it  left  on  an  acre  would  produce  about  a  ton  of  sugar.  The 
area  counted  over,  in  this  particular  case,  was  representative  of  200  acres. 

A  few  years  ago,  when  the  leaf-hopper  was  at  the  height  of  its  glory  in  reducing 
the  vigour  and  vitality  of  your  canes,  these  figures  would  have  been  much  higher. 
I  have  been  assured  that,  at  that  time,  there  were  acres  and  acres  of  cane  to  be  seen 
on  which  the  majority  of  the  sticks  had  been  ruined  by  rind  disease. 

Apart  from  the  direct  and  indirect  injury  of  the  leafhopper  {Perk- 
in-neTla  seieclieirlcida  Kirk.),  the  sugar-cane  borer  (Sphenophorus 
obscurus  Boisd.),  the  sugar-cane  leaf-roller  (Omiodes  eiccepta  Butler), 
and  other  minor  pests  contributed  to  the  loss  sustained. 

The  explanation  of  the  undue  increase  on  the  part  of  the  leaf- 
hopper is  made  clear  when  it  is  known  that  up  to  the  time  of  the 
leafhopper  invasion  the  sugar  plantations  had  been  particularly  free 
from  serious  attacks  of  hisect  and  disease  pests.  The  planters  were, 
therefore,  unacquainted  with  the  insect  life  to  be  found  in  their  cane 
fields.  They  did  not  know  the  source  or  nature  of  the  leafhopper 
attack  and  had  at  hand  no  general  knowledge  of  insect  warfare. 
The  injury  of  the  leafhopper,  combined  with  that  of  the  other  species 
mentioned,  and  the  complications  arising  through  the  development 
of  certain  diseases  gave  the  leafhopper  a  favorable  opportunity  to 
develop  great  numbers  in  those  localities  where  climatic  influences 
or  soil  conditions  were  unfavorable  to  the  sugar  cane  or  where  a 
deteriorated  condition  of  the  cane  varieties  prevailed. 

°  Report  Governor  of  Hawaii  for  fiscal  year  1907.  p.  22. 

&Lewtox-Brain\  L.—  Rind  Disease  of  the  Sugar-Cane.  <Hawaiian  Sugar  Plant- 
ers' Exp.  Sta.,  Div.  Path.,  Bui.  7,  p.  15,  1907. 


20  THE    SUGAR-CANE    INSECTS    OF    HAWAII. 

FACTORS    RESPONSIBLE    FOR    THE    OUTBREAK   OF    1903. 

On  those  plantations  where  the  outbreak  of  the  leafhoppers  became 
epidemic  the  writer  made  careful  observations  to  determine,  if  pos- 
sible, the  conditions  of  season,  soil,  varieties,  or  methods  of  cultiva- 
tion which  might  have  contributed  to  the  leafhopper  development. 
Some  of  these  conditions  noted  will  be  mentioned. 

(1)  The  season  during  which  the  attack  was  most  serious  was  not 
the  growing  season,  and  in  some  localities  the  weather  was  most 
unfavorable  for  the  growth  of  the  cane.  In  one  instance,  for  example, 
there  were  during  one  month  24  rainy  days  out  of  the  30:  and  since 
the  temperature  on  a  rainy  day  is  some  ten  degrees  lower  than  on  a 
bright  day,  and  because  of  the  absence  of  sunshine  to  carry  on  the 
work  of  assimilation,  a  less  vigorous  growth  of  cane  resulted. 

(2)  The  long  duration  of  prevailing  high  winds. 

(3)  An  impoverished  condition  of  the  soil.  Certain  fields  in  which 
the  leafhopper  was  epidemic  had  been  planted  continuously  to  cane 
for  over  20  years.  The  soil  in  certain  parts  of  some  fields,  also, 
where  the  leafhopper  infestation  was  greatest  was  found  to  be  in  poor 
condition  because  of  lack  of  drainage. 

(4)  As  the  rainy  season  was  followed  by  a  long  period  of  dry  weather, 
without  the  means  of  irrigation,  the  cane  lacked  sufficient  moisture 
to  enable  it  to  put  forth  a  vigorous  growth.  This  point  was  demon- 
strated on  an  unirrigated  plantation  in  the  district  of  Kohala,  Hawaii. 
A  portion  of  a  field  was  seriously  attacked  by  the  leafhopper  during 
the  month  of  September,  1903,  after  several  months  of  dry  weather. 
The  manager  of  the  plantation,  Mr.  E.  E.  Olding,  was  able  to  run 
water  into  this  portion  of  the  field  and  irrigated  the  cane  four  times 
at  intervals  of  about  a  week,  with  the  result  that  the  cane,  although 
showing  the  attack  in  the  smallness  of  the  joints  grown  during  that 
time,  recovered,  and  when  the  writer  visited  the  field  during  the 
month  of  November  of  the  same  year  was,  in  appearance,  not  unlike 
healthy  portions  of  the  same  field. 

(5)  The  presence  of  other  pests,  principally  the  cane  borer  (Spin  n- 
ophorus  obscurus)  and  the  leaf-roller  (Omiodes  accepta). 

(6)  The  lack  of  thorough  cultivation. 

(7)  The  injury  to  cane  on  the  makai  (seaward)  fields  by  the  salt 
spray  or  the  check  to  the  cane  by  the  cold  on  the  mauka  (mountain- 
ward)  fields. 

(8)  The  deterioration  of  varieties. 

(9)  The  complications  due  to  the  presence  of  certain  diseases. 

THE    LEAFHOPPER    AND    BEEKEEPING. 

An  interesting  condition  of  affairs  arising  from  the  leafhopper 
attack  on  sugar  cane  is  the  collection  of  the  honey  dew  by  honey  bees. 
The  increase  in  the  production  of  Hawaiian  honey  of  recent  years 


THE   LEAFHOPPER    AND    BEEKEEPING. 


21 


corresponds  with  the  advent  of  the  sugar-cane  leafhopper  into  the 
cane  fields,  and  the  recent  extensive  proportions  which  the  bee- 
keeping business  in  the  islands  is  assuming  is  in  the  vicinity  of  the 
immense  areas  of  land  given  to  cane  culture.0     (See  fig.  2.) 

The  principal  source  of  floral  honey  in  the  islands  is  the  flowers  of 
the  algeroba  (Prosopis  juliflora).  The  total  production  of  this  floral 
honey  does  not  exceed  600  tons.  The  output  of  honey  for  1910  in 
the  islands  exceeds  1,000  tons,  and  the  remaining  400  tons  consists 
almost  entirely  of  the  product  gathered  from  the  honeydew  of  the 
sugar-cane    leafhopper.     Some    100    tons    of    this    forms    a    typical 


Fig.  2.— An  apiary  near  a  sugar-cane  field.    (From  Phillips.) 

hone3^dew  honey,  the  remaining  amount  consisting  of  natural  blends 
of  these  two  types. 

Honeydew  honey  from  the  sugar-cane  leafhopper  is  noncrystal- 
lizable  and  usually  of  a  very  dark  color.  The  aroma  is  very  similar 
to  that  of  molasses  and  the  taste  insipid.  The  product  is  abnor- 
mally high  in  ash,  the  amount  ranging  from  1  to  2  per  cent,  and  it 
has  a  decided  right-handed  polarization,  while  the  floral  or  algeroba 
honey   is   low  in    ash    and    has    a    left-handed    rotation,    which    is 


"Van  Dine,  D.  L. — The  Source  and  Characteristics  of  Hawaiian  Honeys. 
<Hawaii  Agr.  Exp.  Sta.,  Bui.  17.  Pt.  I,  pp.  1-12,  1908. 

Phillips,  E.  F. — A  brief  survey  of  Hawaiian  Bee  Keeping.  <JJ.  S.  Dept.  Agr., 
Bur.  Ent.,  Bui.  75,  Pt.  V,  Jan.  19,  1909. 


22  THE    SUGAR-CANE   INSECTS   OF    HAWAII. 

characteristic  of  all  floral  honeys.  The  larger  amount  of  honey- 
dew  is  obtained  from  the  insects  on  the  young  plant  cane, 
for  there  the  leafhoppers  are  more  abundant.  The  amount  of 
honey  dew  gathered  depends  on  the  maturity  of  the  cane  and  the 
amount  of  rain  which  washes  the  secretion  from  the  leaves. 

CONTROL    OF    THE    LEAFHOPPER. 

Direct  Measures. 

Insecticides. — Those  familiar  with  the  culture  of  sugar  cane  will 
readily  understand  the  difficulty  of  getting  hi  and  through  the 
fields  after  the  cane  obtains  smy  height.  This  difficulty  renders  the 
use  of  insecticides  as  a  remedy  unpractical.  In  Hawaii  such  a 
method  becomes  still  more  difficult  because  of  the  prevailing  slope 
of  the  cane  lands  and  the  manner  in  which  the  fields  in  many  dis- 
tricts are  laid  out  for  purposes  of  irrigation.  The  feeding  habits 
of  the  leafhopper  are  such  that  a  contact  poison  or  irritant  would  be 
necessary  for  its  destruction,  and  the  activity  of  the  leafhoppers — 
that  is,  the  suddenness  with  which  they  disperse  at  the  least  dis- 
turbance— still  further  prevents  the  successful  application  of  a  con- 
tact insecticide.  Then,  too,  the  cane  fields  of  Hawaii  are  subject 
to  prevailing  winds,  which  greatly  interfere  with  the  use  of  any 
substance  in  the  form  of  a  spray.  In  the  face  of  the  above  diffi- 
culties the  writer  attempted  the  destruction  of  the  leafhopper  by 
direct  measures  and  found  that  an  application  of  kerosene  emulsion 
applied  in  the  shape  of  a  finely  divided  stream  with  considerable 
force  was  capable  of  killing  only  a  small  percentage.  A  mixture  of 
lime  and  caustic  soda  was  also  applied,  with  negative  results.  Lime, 
prepared  by  reducing  fresh  stone  lime  to  a  powder  by  the,  use  of 
solutions  of  copper  sulphate  and  caustic  soda,  was  applied  as  a  dust 
on  cloudy  days,  or  just  after  showers,  and  while  in  comparison  to 
spraying  a  much  larger  area  was  covered,  and  the  dust  came  in 
contact  with  a  large  percentage  of  the  leafhoppers,  no  appreciable 
beneficial  results  were  observed. 

(  ollection  by  nets. — Ordinary  sweeping  nets  supplied  with  short 
handles  were  placed  in  the  hands  of  the  laborers,  and  the  leafhoppers 
were  collected  by  having  the  laborers  go  in  a  body  through  adjoining 
rows  and  sweep  the  nets  over  the  cane  leaves.  The  insects  collected 
were  dumped  from  the  nets  into  buckets  of  water  and  kerosene  at 
the  ends  of  the  rows.  While  immense  numbers  were  captured  in 
this  way,  the  number  collected  and  the  area  covered  were  so  small 
in  comparison  to  the  abundance  of  the  leafhoppers  and  to  the  extent 
of  the  infested  area  that  this  measure  was  also  discarded. 

Cutting  and  burning  in  the  infested  centers. — The  direct  measures 
of  control  advised  by  the  writer  were  confined  to  the  cutting  down 


THE    SUGAR-CANE   LEAFHOPPER.  23 

and  burning  over  of  those  centers  in  the  fields  where  the  species  had 
become  numerous.  In  this  practice  it  was  observed  that  many  of 
the  adults  were  able  to  take  flight  from  the  burning  cane  and  escape 
to  adjoining  fields.  However,  many  adults  and  all  of  the  unhatched 
eggs  in  the  leaves  and  the  immature  wingless  forms  were  destroyed. 
The  center  of  infestation  was  destroyed,  and  this  gave  the  ratoon 
crop  over  these  areas  a  chance  under  more  favorable  conditions. 

Stripping  the  leaves. — For  agricultural  reasons  it  was  a  common 
practice  in  Hawaii  to  strip  the  lower  mature  leaves  from  the  cane 
stalk.  It  was  believed  at  first  that  this  operation  would  greatly 
lesson  the  numbers  of  the  leafhopper  by  the  exposure  of  the  un- 
hatched forms  in  the  leaves  of  the  cane  and  by  removing  a  place  of 
shelter  for  the  active  forms.  Observations  made  during  the  summer 
months  indicated  that  stripping  was  beneficial  from  the  standpoint 
of  the  control  of  the  leafhopper.  Later  observations  made  during 
the  winter  months,  however,  when  growth  of  the  cane  practically 
ceases,  showed  a  very  serious  condition  of  affairs,  namely,  that  in 
heavy  infestation  the  internodes  of  the  stalk  of  stripped  cane  con- 
tained hundreds  of  punctures  from  egg  laying,  while  the  internodes 
of  uns tripped  cane  were  protected  from  such  injury  b}T  the  leaf- 
sheaths. 

Burning  of  trash  after  harvesting. — The  thorough  burning  of  the 
trash  after  the  cane  is  harvested  is  the  most  effective  method  prac- 
ticed for  the  control  of  the  insects  of  sugar  cane.  In  the  case  of 
the  leafhopper  many  of  the  adults  no  doubt  take  flight,  but  the 
destruction  to  the  eggs  and  immature  forms  in  the  trash  is  enormous. 
The  place  where  the  greatest  numbers  of  the  leafhopper  were  noted 
in  1903  was  on  a  plantation  where  the  practice  of  " burning  off" 
had  been  discontinued  for  several  years,  and  the  manager  attributed 
the  unusual  increase  of  the  pest  to  the  fact  that  the  trash  had  not 
been  burned.  Both  for  the  leafhopper  and  the  cane  borer,  burning  off 
has  become  general  once  more. 

Indirect  Measures, 
preventive  methods. 

Selection  of  varieties  of  cane  for  planting. — There  was  noticeable 
in  general  throughout  the  plantations  a  marked  difference  in  the 
power  of  the  different  varieties  to  resist  the  attack  of  the  leafhopper. 
While  the  same  variety  would  vary  in  different  localities  as  regards 
growth  and  resistance,  still  the  difference  between  any  two  varieties 
remained  constant.  For  example,  Yellow  Caledonia  was  invariably 
the  more  resistant  as  compared  to  Rose  Bamboo  and  Lahaina,  and 
while  the  former  was  more  seriously  attacked  in  some  localities  than 
in  others,  wherever  the  opportunity  offered  itself  for  comparison  with 
the  latter,  the  Yellow  Caledonia  made  the  best  showing.     It  is  for 


24 


THE    SUGAR-CANE    INSECTS    OF    HAWAII. 


the  planter  to  decide  whether  or  not  the  advantages  of  one  variety 
over  another  are  offset  by  the  ravages  of  the  leafhopper.  If  the  loss 
from  the  leafhopper  is  greater  than  the  gain  in  the  yield  between  any 
two  varieties  in  the  absence  of  the  leafhopper,  then  it  is  policy  to 
select  the  more  resistant  cane. 

The  Yellow  Caledonia  (fig.  3)  is  a  hardy  cane  and  the  plant  makes 
a  vigorous  growth.  These  qualities,  together  with  the  showing  which 
the  variety  made  during  the  leafhopper  epidemic,  have  made  the 
cane  a  popular  variety  in  the  Hawaiian  Islands.     Mr.  C.  F.  Eckart, 


Fig.  3.— Yellow  Caledonia  sugar  cane,  a  variety  which  is  replacing  Lahaina  and  Rose  Bamboo  in  the 
Hawaiian  Islands.    Photograph  taken  during  the  leafhopper  epidemic  of  1903.    (Original.) 

Director    of    the    Hawaiian    Sugar    Planters'    Experiment    Station, 
reports  as  follows  on  this  cane:a 

Probably  no  subject  pertaining  to  the  cultivation  of  cane  in  the  Hawaiian  Islands 
during  recent  years  has  held  more  interest  for  the  planters,  in  various  localities,  than 
that  relating  to  the  introduction  and  trial  of  new  varieties. 

In  the  Hilo  and  Hamakua  districts,  the  Lahaina  first  made  way  for  the  Rose  Bamb<  n  >, 
and  the  latter,  after  a  strong  stand  for  many  years,  is  now  being  rapidly  succeeded  by 
the  more  vigorous  Yellow  Caledonia.  This  cane  with  its  upright  growth  and  deep 
routing  propensities  has  proved  a  most  valuable  acquisition  in  wet  and  dry  localities 
alike.  Growing  erect,  with  a  natural  tendency  to  shed  its  dried  leaves,  it  becomes 
an  admirable  cane  for  rainy  districts,  where  varieties  that  are  prone  to  fall  to  the 
ground  and  remain  in  contact  with  a  frequently  saturated  soil  have  shown  extreme 

a  Eckart,  C.  F. — Varieties  of  cane.  <Report  of  the  Experiment  Station  Com- 
mittee, Hawaiian  Sugar  Planters'  Association,  for  the  year  ending  September  30,  1904, 
Appendix  IV,  p.  31. 


THE    SUGAR-CANE    LEAFHOPPER.  25 

sensitiveness.  The  frequent  stripping,  required  for  Lahaina  and  Rose  Bamboo  in 
these  wet  places,  has  necessarily  added  to  the  cost  of  cultivation,  and  the  ready  manner 
in  which  Yellow  Caledonia  tends  to  strip  itself  is  no  small  item  in  favor  of  economy. 
Again  the  manner  in  which  it  keeps  down  weeds,  which  were  such  a  menace  to  its 
predecessors  on  the  unirrigated  plantations,  is  another  strong  point  in  its  favor.  In 
dry  districts  subject  to  occasional  drought,  it  has  amply  demonstrated  its  hardihood 
over  Rose  Bamboo,  which  in  turn  is  more  resistant  to  such  unfavorable  climatic  features 
than  Lahaina.  By  sending  its  roots  down  deep  into  the  soil  it  draws  from  a  larger 
reserve  supply  of  water  than  the  older  varieties,  which  are  more  shallow  feeders  and 
which  soon  feel  the  effects  of  a  rainless  period. 

Dr.  R.  C.  L.  Perkins  reports  as  follows  on  the  relative  immunity 
of  different  varieties  of  cane  from  leaf  hopper  attack:0 

It  seems  certain  that  some  varieties  of  cane  will  stand  the  attack  of  leaf -hopper 
better  than  others.  Mr.  Eckart,  Director  of  the  Hawaiian  Sugar  Planters'  Experiment 
Station,  has  furnished  me  with  a  list  of  new  varieties  of  cane  (see  Appendix,  Xote  II 
below),  grown  there,  arranged  in  order,  according  to  the  relative  injury  that  each 
sustained  from  leaf -hopper. 

There  may  come,  however,  so  severe  an  attack  that  no  cane  can  resist  it.  Thus 
we  have  seen  plants  of  "Yellow  Caledonia"  (at  the  extreme  end  of  the  list)  which 
were  of  the  strongest  and  most  thrifty  nature  previous  to  the  attack,  some  entirely 
destroyed  and  others  very  badly  injured  after  a  bad  outbreak.  It  is,  however,  prob- 
able that  from  an  attack  of  hopper  which  would  entirely  destroy  a  field  of  "Rose 
Bamboo,"  for  instance,  a  field  of  "Yellow  Caledonia"  might  recover. 

The  following  is  the  note  to  which  Doctor  Perkins  refers  above: 

The  following  list  of  new  varieties  (i.  e.,  varieties  other  than  the  old  standard  ones 
of  these  islands)  of  cane  at  the  Hawaiian  Planters'  Experiment  Station  has  been  drawn 
up  for  me  by  Mr.  C.  F.  Eckart,  the  Director.  They  are  arranged  in  order,  according 
to  the  amount  of  damage  sustained  from  leaf-hopper  attack,  Queensland  4  suffering 
most  and  Yellow  Caledonia  least: 


(1)  Queensland  4 

(2)  Queensland  1 

(3)  Queensland  8 A. 

(4)  Louisiana  Purple 

(5)  Demerara  95 

(6)  Gee  Gow 

(7)  Cavengerie 

(8)  Demerara  74 

(9)  Yellow  Bamboo 


(10)  Tiboo  Merd 

(11)  Louisiana  Striped 

(12)  Striped  Singapore 

(13)  Big  Ribbon 

(14)  Queensland  7 

(15)  Demerara  117 

(16)  White  Bamboo 

(17)  Yellow  Caledonia. 


Cultural  methods  on  the  'plantation. — The  writer  has  already  men- 
tioned the  fact  that  the  epidemic  of  1903  began  during  the  winter 
months,  in  a  wet  season,  and  at  a  time  when  the  cane  was  making 
practically  no  growth.  The  centers  from  which  the  infestation  spread 
over  the  cane  fields  were  invariably  unfavorable  locations  for  growth. 
It  has  been  noted  in  this  report  that  all  varieties  suffered  in  these 
unfavorable  locations  but  that  certain  varieties  made  a  better  show- 
ing.    The   extension  of  the   acreage   of  one   variety  in  particular, 

a  Perkins,  R.  C.  L. — The  leaf -hopper  of  the  sugar-cane.     <Bd.  of  Agr.  and  For- 
estry, Hawaii,  Div.  Ent.,  Bui.  1,  p.  13,  1903. 
83327°— Bull.  93—11 4 


26  THE    SUGAR-CANE    INSECTS    OF    HAWAII. 

Yellow  Caledonia,  will  be  a  leading  factor  in  preventing  another 
epidemic.  One  other  point  was  brought  home  to  the  Hawaiian 
planters  as  a  result  of  the  leafhopper  epidemic,  and  that  was  the 
importance  of  intensive  cultivation.  The  grass  and  weeds  must  be 
kept  down  by  cultivation,  the  low  places  drained,  and  the  impover- 
ished lands  fertilized.  Those  plantations  which  were  in  a  high  state 
of  cultivation  suffered  less  from  the  leafhopper  attack,  and  the  estates 
provided  with  the  means  of  irrigation,  in  addition,  suffered  the  mini- 
mum loss.  There  is  a  direct  relation  between  intensive  cultivation, 
fertilization,  and  irrigation  and  the  amount  of  insect  injury  to  any 
crop,  showing  that  these  operations  are  of  great  value  in  lessening 
insect  damage. 

Diversification  of  crops. — Sugar  cane  has  been  the  leading  crop  in 
Hawaii  since  the  days  when  the  islands  turned  from  the  sandal-wood 
trade  and  the  whaling  fleet  as  a  source  of  revenue.  Some  of  the  lands 
have  been  under  cultivation  to  cane  continuously  for  over  twenty-five 
years.  The  time  is  at  hand  when  the  sugar-cane  planters  will  find 
it  both  necessary  and  more  profitable  to  diversify  their  crop.  Some 
lands  at  present  require  a  change  from  sugar  cane,  and  the  lands  which 
are  still  highly  productive  will  also  require  such  a  change  as  the  years 
go  by.  When  the  general  practice  of  inter-cropping  cane  with  other 
plants  does  come,  it  will  have  a  direct  bearing  on  the  control  of  the 
sugar-cane  insects,  the  leafhopper  included.  The  intermediate  crop 
may  be  one  of  value  in  itself  or  one  to  be  plowed  under  for  green 
manure.  Since  it  is  not  wise  to  cease  the  practice  of  burning  off  the 
trash  after  harvesting  the  cane,  the  planters  can  find  no  cheaper  source 
of  plant  food,  or  no  way  in  which  the  requisite  texture  and  water- 
holding  capacity  of  the  soil  can  be  more  easily  obtained  than  by 
removing  their  lands  from  cane  cultivation  in  regular  rotation  and 
planting  some  nitrogen-gathering  plant  to  be  turned  under  when  the 
land  is  put  back  into  cane. 

Control  of  the  rind  disease  of  sugar  cane. — As  has  been  mentioned, 
leafhopper  injury  is  aggravated  by  the  presence  of  the  rind  disease. 
In  a  discussion  of  the  rind  disease  (Melanconium  sacchari)  Dr.  X.  A. 
Cobb  says:  a 

According  to  my  observations  on  thousands  of  cuttings  dug  up  on  some  twenty-five 
plantations  a  considerable  part  of  the  cuttings  in  some  fields  fail  to  grow  on  account 
of  this  disease,  which,  being  present  in  the  cuttings  when  they  are  planted,  develops 
sufficiently  to  prevent  germination.  This  is  a  difficult  thing  wholly  to  avoid  by 
means  of  inspection  of  the  seed,  as  the  disease  is  sometimes  present  in  cane  that  looks 
sound.  It  may  be  suspected  to  be  present  in  any  cane  that  has  been  attacked  on  the 
stalks  by  leaf -hopper  or  by  borers.  Other  wounds  that  give  admission  to  the  rind 
disease  fungus  are  those  made  by  injudicious  stripping,  cracks  at  the  bottom  of  the 
cane  due  to  the  effects  of  storms,  and  what  are  sometimes  called  "growth  cracks." 

a  Cobb,  N.  A. — Fungus  maladies  of  the  sugar  cane.  <Hawaiian  Sugar  Planters' 
Exp.  Sta.,  Div.  Path.,  Bui.  5,  p.  107,  1906. 


THE    SUGAR-CANE   LEAFHOPPER.  27 

Cane  raised  specially  for  seed  and  not  stripped  until  wanted  for  planting  is  more 
likely  to  be  free  from  insect  punctures,  and  will  therefore  be  less  likely  to  develop 
rind  disease  after  planting. 

Mr.  L.  Lewton-Brain  in  a  report  on  the  rind  disease  thus  describes 
the  relation  between  the  leaf  hopper  and  the  disease :  a 

Under  field  conditions,  of  course,  the  spores  gain  access  to  the  interior  of  the  plant 
through  natural  wounds.  Perhaps  the  most  abundant  wounds  offered  for  this  pur- 
pose are  leafhopper  punctures;  even  more  favorable  for  the  fungus  are  the  tunnels  of 
borers,  leading  as  they  do  right  into  the  heart  of  the  sugar-containing  tissue;  other 
wounds  may  be  made  in  stripping;  in  fact,  it  is  a  difficult  matter  to  find  a  stalk  of 
cane  without  a  wound  of  some  sort.  The  spores  are  produced  in  immense  numbers 
on  every  stick  of  rotten  cane.  They  are  doubtless  distributed  partly  by  the  wind, 
though  the  mucilaginous  substance  by  which  they  are  joined  does  not  favor  this; 
insects  are  certainly  also  important  distributers  of  the  spores,  leafhoppers  will  get 
infected  and  deposit  the  spores  in  their  punctures,  ants  will  carry  them  into  borer 
and  other  wounds  in  their  search  for  food,  flies  may  also  serve  the  fungus  in  the  same 
way. 

The  control  of  the  rind  disease  of  cane  on  the  plantation  will  be 
another  factor  in  reducing  leafhopper  injury.  Since  the  leafhopper 
can  not  be  exterminated  and  the  punctures  from  this  insect  will 
always  occur  on  a  plantation  to  a  greater  or  less  degree,  it  becomes 
particularly  essential  for  the  planter  to  eradicate  the  disease. 

On  the  control  of  the  rind  disease,  Doctor  Cobb  has  the  following 
on  pages  109  and  110  of  his  report  referred  to  above: 

The  number  of  spores  of  this  disease  that  exist  on  every  plantation  is  past  calcula- 
tion, and  almost  inconceivable.  This  abundance  of  the  spores  of  the  disease  tends 
of  course  to  increase  the  losses.  If  there  were  no  spores  there  .could  be  no  rind  dis- 
ease. Anything  that  can  be  done  to  reduce  the  number  of  spores  will  tend  to  reduce 
the  amount  of  the  disease.  Something  can  certainly  be  done  in  this  direction.  Stalks 
dead  of  the  disease  can  be  destroyed,  and  there  can  be  no  doubt  that  in  some  cases 
expenditure  in  this  direction  will  be  well  repaid.  There  can  be  no  doubt  that  the 
collecting  and  complete  destruction  of  the  stalks  on  the  field  would  be  a  paying 
operation.  How  to  destroy  them  is  the  question.  The  ordinary  burning  off  destroys 
only  a  part  of  these  rind  disease  stalks,  leaving  the  rest  untouched  or  only  partially 
roasted,  to  go  on  producing  their  millions  upon  millions  of  spores. 

It  is  the  custom  on  all  the  Hawaiian  plantations  to  leave  on  the  ground  after  harvest 
the  sticks  of  cane  that  have  been  attacked  by  borers  or  are  worthless  for  other  reasons. 
The  reason  for  this  is  easy  to  understand.  Such  material  is  unsuitable  to  the  highest 
efficiency  of  the  mill  as  an  extractor  of  cane  juice.  It  is  also  of  such  a  nature  that 
it  may  interfere  with  the  clarification,  evaporation,  or  crystallization. 

Notwithstanding  this  I  think  it  would  be  advisable  to  consider  whether  this  material, 
which  is  really  a  menace  to  the  health  of  future  crops,  cannot  in  some  way  be  run 
through  the  mill  and  burned.  This  is  a  practice  adopted  in  some  other  parts  of  the 
world.  On  Saturday  afternoons  a  special  run  of  the  mill  is  devoted  to  the  milling  of 
such  refuse  as  I  have  mentioned,  the  "bagasse"  being  burned.  The  juice  is  allowed 
to  run  to  waste,  being  first  sterilized  by  heat. 

In  Hawaii  it  is  usual  to  attempt  to  burn  this  diseased  material,  but  from  careful 
observation  I  am  certain  that  this  attempt  often  ends  in  failure,  that  is  to  say  the 
disease  that  exists  in  the  waste-cane  is  only  partially  destroyed. 

a  Lewton-Brain,  L. — Rind  disease  of  the  sugar  cane.  <Hawaiian  Sugar  Planters' 
Exp.  Sta.,  Div.  Path.,  Bui.  7,  p.  21,  1907. 


28  THE    SUGAR-CANE    INSECTS    OF    HAWAII. 

It  may  be  that  it  would  be  better,  at  least  from  the  disease  point  of  view,  if  the 
harvesting  of  the  fields  were  more  in  the  nature  of  a  clean  sweep.  If  the  diseased 
sticks  are  not  too  numerous  they  would  not  seriously  interfere  with  the  working  of 
the  mill.  The  advantage  would  be  that  whatever  diseased  material  was  thus  dealt 
with  would  be  dealt  with  in  the  very  best  manner,  that  is,  it  would  be  utterly  de- 
stroyed. 

NATURAL    ENEMIES. 

Species  Already  Present  in  the  Islands. 

Many  beneficial  species  of  insects,  already  present  in  the  islands 
at  the  time  of  the  leaf  hopper  invasion,  adapted  themselves  to  the 
leafhopper  as  a  source  of  food.  The  following  species  were  noted 
during  1903: 

A  ladybird  beetle,  Coccinella  repanda  Thunb.,  one  of  Mr.  Koebele's 
Australian  introductions,  was  particularly  abundant  in  the  cane 
fields  and  the  larva  did  good  work  against  the  young  leafhoppers. 
An  enemy  of  this  species,  the  hymenopterous  parasite  Centistes 
americana  Riley,  has  found  its  way  to  the  islands  and  will  no  doubt 
reduce  the  effectiveness  of  the  ladybird.  The  writer  observed  also 
the  ladybird  Platyomus  lividigaster  Muls.  in  the  cane  fields.  A 
predaceous  bug,  CEchalia  griseus  Burm.,  was  found  in  large  numbers 
m  the  infested  cane  fields  on  the  Island  of  Hawaii.  The  larvae  of 
two  lace  wing  flies,  Chrysopa  micropJiya  McLachl.,  and  Anomalochrysa 
sp.,  were  observed  feeding  on  the  young  leafhoppers,  the  first  species 
being  particularly  abundant  in  some  localities. 

Several  species  of  spiders  were  abundant  in  the  cane  fields  and 
were  active  enemies  of  the  leafhopper.  The  writer  collected  two 
species,  Tetragnaiha  mandibulata  Walck.  and  Adrastidia  nebulosa 
Simon.  On  the  writer's  advice  large  numbers  of  the  egg-nests  of 
spiders  were  collected  in  the  localities  where  they  were  abundant 
and  placed  in  sections  where  they  had  not  as  yet  become  established 
in  the  cane  fields. 

In  the  forest  above  the  Kohala  district,  on  the  island  of  Hawaii, 
the  writer  found  a  fungous  disease  infecting  to  a  great  extent  the 
common  leafhopper  Siphanta  acuta  Walk.,  a  species  belonging  to  the 
same  family  as  the  cane  leafhopper.  Quantities  of  this  fungus 
were  distributed  in  the  cane  fields  in  the  hope  that  it  would  infest 
the  cane  leafhopper.  No  striking  results  were  obtained,  though 
diseased  cane  leafhoppers  were  found  in  some  of  the  rainy  districts. 

Several  species  of  ants  were  very  active  about  the  leafhoppers  in 
the  cane  fields,  the  honeydew  being  an  attraction  to  them. 

Doctor  Perkins  mentions  further  in  his  early  report  a  predaceous 
bug,  Zelus  peregrinus  Kirk.,  and  describes  as  new  a  hymenopterous 
parasite  of  the  leafhopper  under  the  name  Ecthrodelphax  fair- 
childii  Perk.a 

a  Perkins,  R.  C.  L. — Bd.  Comrs.  Agr.  and  Forestry,  Hawaii,  Div.  Ent.,  Bui.  1, 
pp.  20-22. 


THE    SUGAR-CANE    LEAFHOPPER.  29 

More  recently  the  species  of  beneficial  insects  which  were  already 
present  in  the  islands  when  the  leafhopper  was  introduced  and 
which  have  sought  the  leafhopper  in  the  cane  fields  have  been  reported 
upon  in  detail  by  the  entomologists  of  the  Hawaiian  Sugar  Planters' 
Experiment  Station.0 

Special  Introductions. 

In  1903  Mr.  Albert  Koebele,  after  consulting  with  Dr.  L.  O.  How- 
ard, undertook  extensive  observations  on  the  American  parasites  of 
leaf  hoppers.  In  Ohio  Mr.  Koebele  had  the  assistance  of  Mr.  Otto 
H.  Swezey.  A  large  quantity  of  living  material  was  collected  both 
in  Ohio  and  in  California  and  shipped  to  Doctor  Perkins  at  Honolulu. 
The  American  material  consisted  in  the  main  of  insects  belonging 
to  the  hymenopterous  family  Dryinida?.  The  Hawaiian  parasite 
Ecthrodelpliqx  faircMldii  Perkins  is  also  a  member  of  this  family 
and,  at  the  time  of  Mr.  Koebele 's  American  introductions,  was 
being  reared  and  distributed  over  the  islands  by  Doctor  Perkins. 
These  introductions  are  discussed  by  Doctor  Perkins  in  Part  I  of 
Bulletin  1,  Division  of  Entomology,  Hawaiian  Sugar  Planters' 
Experiment  Station,  1905.& 

Mr.  Koebele  also  collected  during  his  American  investigations 
representatives  of  the  order  Strepsiptera  (Stylopidre)  and  a  single 
species  of  an  egg-parasite,  Anagrus  columbi  Perk.,  belonging  to  the 
family  Mymarida?. c 

In  the  spring  of  1904  Messrs.  Koebele  and  Perkins  sailed  for 
Australia  to  continue  the  search  for  parasites  of  the  leafhopper. 
They  reached  Sydney  in  May  and  because  of  the  cold  weather  which 
prevailed  they  proceeded  to  Brisbane.  The  results  of  the  work  in 
Australia  are  thus  summarized  by  Doctor  Perkins :d 

Early  in  June  we  arrived  at  Brisbane,  and  on  the  first  cariethat  we  saw,  a  few  plants 
in  the  public  gardens,  we  at  once  observed  the  presence  of  the  cane  leaf-hopper.     A 

a  Leafhoppers  and  their  natural  enemies.  ^Hawaiian  Sugar  Planters'  Exp.  Sta., 
Div.  Ent.,  Bui.  1. 

Perkins,  R.  C.  L.— Part  I,  pp.  1-60,  May,  1905.     (Ecthrodelphax  fairchildii .) 

Perkins,  R.  C.  L. — Part  IV,  pp.  113-157,  pis.  5-7,  September,  1905.     (Pipunculidse.) 

Terry,  F.  W— Part  V,  pp.  159-181,  pis.  8-10,  November,  1905.  (Forficulidse, 
Syrphidse  and  Hemerobiidse.) 

Swezey,  O.  E.— Part  VII,  pp.  207-238,  pis.  14-16,  December,  1905.  (Orthoptera, 
Coleoptera,  and  Hemiptera.) 

b  Perkins,  R.  C.  L. — Leafhoppers  and  their  natural  enemies.  <Hawaiian  Sugar 
Planters'  Exp.  Sta.,  Div.  Ent.,  Bui.  1,  Part  I,  pp.  1-60,  May,  1905.     (DryinidaB.) 

c  Perkins,  R.  C.  L. — Leafhoppers  and  their  natural  enemies.  <Hawaiian  Sugar 
Planters'  Exp.  Sta.,  Div.  Ent.,  Bui.  1,  Pt.  Ill,  pp.  86-111,  pis.  1-4,  August,  1905. 
(Stylopidoe.) 

Perkins,  R.  C.  L. — Leafhoppers  and  their  natural  enemies.  <Hi;waiian  Sugar 
Planters'  Exp.  Sta.,  Div.  Ent.,  Bui.  1,  Pt.  VI,  p.  198,  November,  1905.  (Anagrus 
columbi.) 

d  Perkins,  R.C.L. — Leafhoppers  and  their  natural  enemies.  <Hawaiian  Sugar 
Planters'  Exp.  Sta.,  Div.  Ent.,  Bui.  1,  introduction,  pp.  in,  iv,  May,  1906. 


30  THE    SUGAR-CANE    INSECTS    OF    HAWAII. 

short  stay  of  about  ten  days  ga\e  ample  proof  of  the  existence  in  Australia  of  a  con- 
siderable variety  of  Hymenopterous  parasites  of  leaf-hoppers,  of  Dipterous  parasites 
of  the  genus  Pipunculus,  and  of  Stylopid  parasites  of  the  genus  Elenchus. 

At  Bundaberg,  about  twelve  hours  by  rail  north  of  Brisbane,  we  spent  another 
ten  days  in  June.  Here  is  an  extensive  cane  district  with  our  leaf-hopper  every- 
where present,  but  nevpr  in  numbers  such  as  we  are  accustomed  to  in  these  islands. 
In  fact  we  never  saw  the  hoppers  nearly  as  numerous  as  they  are  on  our  least  affected 
plantations.  From  eggs  collected  here  Mr.  Koebele  soon  bred  out  specimens  of  the 
Mymarid  parasites  he  had  felt  so  confident  of  finding. 

From  our  observations  on  the  habits  of  the  cane  leaf-hopper  in  these  islands,  it 
seemed  probable  that  in  tropical  Australia  this  species  would  be  in  its  greatest  num- 
bers in  the  colder  months,  so  after  a  brief  stay  in  Bundaberg,  we  proceeded  north  to 
Cairns,  which  place  we  reached  at  the  beginning  of  July.  This  plan  seemed  very 
expedient,  for  by  retreating  gradually  towards  the  south,  as  the  hot  season  advanced, 
we  hoped  to  prolong  the  season  during  which  natural  enemies  for  the  cane  leaf-hopper 
could  be  obtained.  It  appeared  likely  that  effective  work  could  only  be  done  at 
Cairns  for  a  month  or  two,  since  without  a  reasonably  large  supply  of  hoppers,  it  was 
evident  that  the  parasites  could  not  be  found  in  sufficient  numbers  for  shipment. 
This  indeed  proved  to  be  the  case,  and  by  the  end  of  August,  leaf-hoppers  and  their 
eggs  had  become  so  scarce  in  the  cane  fields,  that  we  came  south  again  to  Bundaberg. 
At  Bundaberg  we  made  a  long  stay  on  this  occasion,  regularly  sending  off  consign- 
ments of  parasite.-,  until  here  too,  owing  partly  to  the  season  and  partly  to  the  harvest- 
ing of  the  crop,  the  locality  became  unprofitable.  After  a  short  stay  in  Brisbane, 
at  the  end  of  the  \  ear,  I  returned  to  Honolulu,  while  Mr.  Koebele  proceeded  to  Sydney, 
where  his  attention  was  largely  given  to  collecting  beneficial  insects  for  pests  other 
than  leaf-hopper.  On  the  return  journey  Mr.  Koebele  spent  one  month  in  Fiji,  the 
enemies  of  the  cane-hopper  in  those  islands  being  mostly  similar  to  those  already 
found  in  Australia.  A  fine  consignment  of  the  Chalcid  egg-parasite  {Ootetrastichus) 
of  leaf-hopper  was  most  important,  as  it  enabled  us  to  establish  that  important  species 
without  any  doubt. 

During  January  and  February,  1906,  Mr.  F.  Muir  continued  the 
work  in  the  Fiji  Islands  begun  by  Mr.  Koebele  in  the  latter  part  of 
1904.  He  reported  as  follows  concerning  the  Fijian  sugar-cane  leaf- 
hopper  and  its  parasites  :a 

The  Fijian  sugar-cane  leaf-hopper  (Perkinsiella  vitiensis)  I  found  all  over  the  island, 
but  it  does  no  damage,  being  kept  in  check  by  several  natural  enemies. 

The  most  important  of  these  are  the  egg-parasites,  Ootetrastichus.  Anagrus  and 
Paranagrus.  The  first  of  these  was  introduced  from  Fiji  into  Hawaii  by  Mr.  Koebele, 
and  the  other  two  appear  to  me  the  same  as  the  Queensland  species.  In  some  fields 
as  many  as  90  %  of  the  hopper  eggs  were  parasitized,  but  in  other  fields  it  was  lower. 
Observations  extending  over  my  six  months'  stay,  and  made  at  the  various  parts  of 
the  island  visited,  show  that  an  average  of  85  %  of  hopper  eggs  were  destroyed  by 
these  parasites.  These  figures  are  only  approximate,  as  I  have  to  estimate  that  one 
Chalcid  {Ootetrastichus)  destroys  four  hopper  eggs,  which  is  a  low  estimate.  This 
Chalcid  is  more  numerous,  and  on  account  of  destroying  the  whole  batch  of  hopper 
eggs,  is  of  very  much  higher  economic  A'alue  than  the  Mymarids. 

a  Muir,  F. — Notes  on  some  Fijian  insects.  <TIawaiian  Sugar  Planters'  Exp.  Sta., 
Div.  Ent.,  Bui.  2,  p.  3,  November,  1906. 


THE    SUGAR-CANE   LEAFHOPPER.  31 

The  Australian  and  Fijian  material  lias  been  described  in  detailed 
reports  with  elaborate  illustrations  by  Messrs.  Perkins,  Terry,  and 
Kirkaldy." 

Regarding  the  effectiveness  of  the  various  parasites  and  enemies  of 
the  leafhopper,  Dr.  Perkins  says:6 

If  we  consider  the  effectiveness  of  the  four  egg-parasites,  Paranagrus  optabilis,  P. 
per/orator,  Anagrus  frequens,  and  Ootetrastichus  beatus,  in  areas  where  all  are  well 
established,  we  must  rate  the  first-named  as  at  present  by  far  the  most  effective.  As  I 
have  previously  pointed  out,  this  species  is  capable  by  itself  of  destroying  about  50 
per  cent  of  the  cane-hopper's  eggs  and  Anagrus  frequens  and  P.  perforator,  extraordi- 
narily numerous  as  they  appear,  where  seen  alone,  are  but  as  isolated  examples  in 
the  crowd,  where  all  are  well  established  in  one  spot.  The  Ootetrastichus  slowly  but 
steadily  increases  in  numbers,  and  on  many  plantations  I  expect  that  it  will  ulti- 
mately be  the  most  efficient  of  all  parasites.  I  do  not  think  that  it  can  show  its  full 
value  till  1908,  for  each  harvesting  of  the  cane  crop  is  necessarily  a  very  great  setback 
to  its  natural  increase.  Anagrus  frequens ,  under  which  name  are  probably  more  than 
one  species,  or  at  least  one  or  two  distinct  races  of  a  single  species,  although  it  appears 
at  a  disadvantage,  when  in  company  with  Paranagrus  optabilis,  is  nevertheless  a 
most  abundant  parasite.  In  Part  VI  of  this  Bulletin  I  have  compared  the  habits  of 
the  two  and  need  not  refer  to  the  matter  here,  but  I  may  say  that  as  many  as  eighty 
or  a  hundred  exit  holes  of  the  Anagrus  have  been  counted  in  a  single  cane-leaf,  so 
that  its  great  utility  is  unquestionable.  P.  perforator,  common  in  Fiji,  attacking 
eggs  of  hopper  laid  in  thick  stems  of  grass,  more  rarely  those  in  cane,  will  probably 
gradually  wander  away  from  the  cane-fields  to  attack  the  eggs  of  native  hoppers,  that 
are  laid  in  stems  and  twigs,  as  it  now  chiefly  attacks  the  cane-hopper  eggs  when  these 
are  laid  in  the  stems. 

Xor  must  it  be  forgotten,  what  valuable  aid  these  egg-parasites  receive  in  the 
control  of  leaf-hopper  from  other  insects  parasitic  and  predaceous,  native  or  introduced. 
In  fact,  had  there  existed  previously  no  restraint  to  the  multiplication  of  the  pest,  no 

a  Hawaiian  Sugar  Planters'  Exp.  Sta.,  Div.  Ent.: 

Perkins,  R.  C.  L.— Bui.  1,  Pt.  I,  pp.  1-69,  May,  1905  (Dryiuidse). 

Perkins,  R.  C.  L—  Bui.  1,  Pt.  II,  pp.  71-85,  figs.  1-3,  June,  1905  (Lepidoptera). 

Perkins,  R.  C.  L.-Bul.  1,  Pt.  Ill,  pp.  86-111,  pis.  1-4,  August,  1905  (Stylo- 

pidse). 
Perkins,  R.  C.  L.— Bui.  1,  Pt.  IV,  pp.  113-157,  pis.  5-7,  September,  1905 

(Pipunculida?). 
Terry,  F.  W—  Bui.  1,  Pt.  V,  pp.  177-179,  November,  1905  (Syrphidse). 
Perkins,  R.  C.  L.— Bui.  1,  Pt.  VI,  pp.  183-205,  pis.  11-13,    November,  1905 

(Mymaridsp,  riatygasteridae). 
Perkins,  R.  0.  L.-Bul.  1,  Pt.  VIII,  pp.  239-267,  pis.  18-20,  January,  1906 

(Hymenoptera). 
Kirkaldy,  G.  W.— Bui.  1,  Pt.  IX,  pp.  269-479,  pis.  21-32,  February,  1906 

(Leafhopper). 
Perkins,  R.  C.  L.— Bui.  1,  Pt.  X,  pp.  481-499,  pis.  33-38,  March,  190G  (Hy- 
menoptera, Diptera). 
Kirkalby,  G.  W.—  Bui.  3,  pp.   1-186,  pis.  1-20,  September,  1907  (Leafhop- 

pers,  Supplement). 
Perkins,  R.  C.  L. — Bui.  4,  pp.  1-59,  May,  1907  (Parasites  of  Leafhoppers). 
&  Perkins,  R.  C.  L. — Leaf-hoppers  and  their  natural  enemies.     <Hawaiian  Sugar 
Planters'  Exp.  Sta,,  Div.  Ent.,  Bui.  1,  introduction,  pp.  xv-xvn,  May,  1906. 


32  THE    SUGAR-CANE   INSECTS   OF    HAWAII. 

one  who  has  paid  the  least  attention  to  such  matters  can  doubt  that  it  would  some  time 
since  have  become  impossible  to  raise  any  crop  of  sugar  cane  in  the  islands.  The  reason 
why  these  natural  enemies  have  not  alone  got  the  upper  hand  of  the  hopper  is  due 
to  various  causes.  In  the  first  place,  a  number  of  the  parasites  such  as  the  Dryinid 
Ecthroclelphax  fairchildii  and  the  parasitic  flies  of  the  genus  Pipunculus  are  of  local 
occurrence,  and  in  many  places  cannot  (for  climatic  or  other  unknown  reasons) 
maintain  their  existence.  This  was  well  shown  by  the  behavior  of  the  first-named, 
which  was  distributed  in  thousands  by  the  entomologists  and  the  Plantation  man- 
agers themselves  to  all  the  districts  in  the  islands,  but  in  many  places  did  not  thrive. 
Such,  too,  is  the  case  with  the  predaceous  black  earwig  (Chelisoches  morio)  which,  a 
natural  immigrant  to  the  islands  and  no  doubt  acclimatised  centuries  ago,  is  found 
on  comparatively  few  plantations.  Other  natural  enemies  are  themselves  periodically 
decimated  by  parasites,  as  is  the  case  with  the  introduced  green  cricket  (Xiphidium 
varipenne),  which  has  its  own  egg-parasite  (Paraphelinus).  Other  enemies  like  the 
common  lady-bird  {Coccinella  repanda)  introduced  by  Koebele  years  ago  for  other 
purposes,  prey  on  young  leaf-hoppers,  in  default  of  more  favorite  food,  and  this  valu- 
able predator  too  is  itself  subject  to  parasitic  attack  by  the  common  Braconid  (Cen- 
tistes).  At  present  the  whole  number  of  parasites  and  predaceous  insects  that  attack 
cane  leaf-hopper  to  such  an  extent  as  to  render  their  services  worth  noting  is  consid- 
erable, as  the  following  summary  shows. 

The  most  valuable  are  the  four  egg-parasites,  which  there  is  every  reason  to  hope 
will  become  still  more  effective  with  reasonable  time,  one  (Ootetrastichus)  having  as 
yet  had  no  chance  to  show  its  full  effectiveness. 

The  two  Pipunculus  flies  (Pipunculus  juvator  and  terryi)  are  restricted  to  certain 
localities  and  are  native  species,  which  have  transferred  their  attacks  from  native 
Delphacids  to  the  cane  leaf-hopper. 

The  ubiquitous  lady-bird  (Coccinella  repanda)  is  valuable  as  a  destroyer  of  leaf- 
hopper,  though  originally  imported  by  Koebele  to  destroy  Aphis.  It  is  hoped  that 
other  lady-birds,  especially  Verania  strigula,  may  become  established  and  do  good 
work,  as  in  Australia  and  Fiji,  whence  they  were  imported. 

The  earwig  Chelisoches  morio  is  a  local  species,  but  no  doubt  useful  where  it  exists 
in  numbers. 

The  green  cricket  (Xiphidium  varipenne)  is  very  valuable,  but  is  most  unfortunately 
heavily  attacked  at  certain  seasons  by  an  egg-parasite. 

The  Dryinid  Ecthrodelphax  fairchildii  is  locally  valuable.  At  certain  seasons  in 
suitable,  but  limited,  localities,  it  destroys  a  considerable  percentage  of  hoppers. 
Its  services  are  underestimated  because  for  a  large  part  of  the  year  it  lies  as  a  dormant 
larva  in  the  cocoon,  and  parasitized  hoppers  at  such  a  time  are  naturally  hardly  to  be 
found. 

There  are  many  other  natural  enemies  of  more  or  less  importance,  e.  g.  the  various 
predaceous  Hemiptera,  and  the  several  lace-wing  flies  (Chrysopinae) . 

In  addition  to  these  insect  enemies,  we  must  mention  the  two  fungous  diseases  of 
hoppers  (amounting  locally  and  at  certain  seasons  to  epidemics)  which,  long  previ- 
ously known  to  kill  the  native  leaf-hoppers,  have  become  transferred  to  the  introduced 
pest.  We  also  found  one  or  more  fungous  diseases  attacking  leaf-hopper  eggs  in  Fiji 
and  Australia  in  all  localities.  With  material  imported  from  these  countries,  I  easily 
infected  eggs  of  the  cane  leaf-hopper  under  cover,  and  subsequently  established  the 
fungus  at  large  in  the  field.  As  it  was  most  probable  that  parasitized  and  healthy 
hopper  eggs  would  be  affected  alike  by  the  disease,  and  consequently  many  of  the  egg- 
parasites  would  be  destroyed,  it  became  a  subject  of  discussion  whether  we  should 
attempt  to  establish  the  fungus  or  not.  As,  however,  throughout  Australia,  the 
fungus  and  parasite  both  attacked  the  eggs,  Mr.  Koebele  was  of  opinion  that  we 
should  try  and  establish  the  same  conditions  here.     Consequently  with  the  first 


THE    SUGAR-CANE   LEAFHOPPER.  33 

cages  sent  to  the  plantations  the  cane  cuttings  and  the  cane  itself  were  well  sprayed 
with  water  containing  spores  of  the  fungous  disease,  so  that  these  would  be  certainly 
carried  abroad  by  the  emerging  hoppers  and  parasites.  I  imagine  there  is  no  doubt 
as  to  this  disease  becoming  established  in  all  suitable  localities. 

In  speaking  of  the  necessity  for  the  continued  propagation  and  dis- 
tribution of  the  introduced  parasites  of  the  leafhopper,  Doctor 
Perkins  reports  as  follows:  a 

Owing  to  the  manner  in  which  cane  is  cultivated  in  these  islands,  the  entomologist 
working  along  the  lines  that  have  been  adopted  to  control  the  leaf-hopper  pest,  meets 
with  a  serious  obstacle  such  as  is  not  encountered  in  dealing  with  insects  injurious  to 
our  other  vegetation.  I  refer  here  to  the  universal  custom  of  burning  off  the  trash  over 
great  acreages,  after  the  crop  has  been  harvested.  I  have  been  told  that  on  the  Colo- 
nial Sugar  Refining  Company's  estates  in  Australia  no  such  burning  off  is  allowed.  If 
this  is  correct,  it  may  help  to  account  for  the  insignificant  numbers  of  our  cane-leaf 
hopper  there,  as  well  as  of  several  other  insects  of  the  same  group,  which  are  fortunately 
not  known  in  our  cane  fields.  As,  however,  burning  of  trash  is  an  established  fact  here, 
it  becomes  necessary  to  see  what  steps  can  be  taken  to  provide  against  this  serious  disad- 
vantage. I  will  first  show  whereof  this  disadvantage  consists.  The  parasitic  enemies 
of  the  leaf-hopper  are  mostly  delicate  and  minute  creatures,  not  accustomed  to  take 
prolonged  flights.  Their  wings  serve  well  to  bear  them  from  plant  to  plant,  but  for  fur- 
ther distribution  they  are  dependent  on  air-currents.  If  when  a  field  of  cane  is  cut  the 
wind  blows  towards  another  cane  field,  no  doubt  some  or  many  parasites  will  reach  it, 
but  if  otherwise,  probably  none  will  do  so.  In  burning  over  a  field  it  is  quite  certain 
that  almost  every  parasite  yet  present  will  be  destroyed,  but  the  adult  leaf-hoppers  on 
the  other  hand  are  well  able  to  take  care  of  themselves.  When,  as  an  experiment,  a 
patch  of  about  nine  acres  of  cane,  so  heavily  attacked  by  leaf-hopper  as  to  be  useless, 
was  set  on  fire  all  around  to  destroy  these,  it  was  noticed  that  the  adult  hoppers  rose 
from  the  cane  in  a  cloud  and  spread  to  other  fields;  so  this  plan  for  destroying  them  was 
of  no  value.  I  have  in  an  earlier  publication  shown  how  quickly  the  leaf-hoppers 
spread  to  new  fields  of  very  young  cane,  and  with  what  regularity  they  distribute  them- 
selves over  the  young  plants.  It  cannot  be  hoped  that  the  parasites  will  (except  under 
rare  and  fortuitous  circumstances,  such  as  constant  favorable  winds)  spread  themselves 
in  like  manner,  and  in  the  same  time.  Yet  it  is  essential  that  the  parasites  should  be 
on  the  spot  when  the  leaf -hopper  begins  to  lay  in  order  to  secure  proper  control.  If  the 
supply  of  laying  hoppers  at  the  beginning  of  the  great  breeding  season  is  very  small,  it 
means  that  there  is  not  time  for  the  attack  to  become  serious  before  that  season  is  over. 
It  is  when  the  hopper  is  least  abundant,  that  one  wants  to  be  assured  that  it  is  being 
attacked  by  all  possible  enemies.  When  a  field  is  already  seriously  injured  and 
swarming  with  hoppers,  not  much  immediate  help  can  be  given  for  obvious  reasons.  It 
will  be  easier  to  prevent  such  a  condition  than  to  find  a  remedy.  If  one  could  provide 
that  in  each  large  area  of  cleared  land,  ready  for  planting,  there  should  be  in  the  middle 
a  small  patch  of  some  variety  of  cane  most  susceptible  to  the  attack  of  leaf-hoppers, 
that  this  cane  should  be  kept  well  stocked  with  these,  and  with  a  variety  of  parasites 
and  predaceous  insects,  and  itself  be  of  sufficient  growth  to  afford  good  shelter  to  all 
these,  the  condition  from  an  entomological  standpoint  would  be  ideal.  This  patch  of 
cane,  being  already  of  suitable  age  and  growth  and  stocked  as  aforesaid,  at  the  time 
the  much  younger  cane  of  the  rest  of  the  field  began  to  be  infested  with  hoppers,  would 

a  Perkins,  R.C.L. — Leaf-hoppers  and  their  natural  enemies.  <Hawaiian  Sugar 
Planters'  Exp.  Sta.,  Div.  Ent.,  Bui.  1,  introduction,  pp.  xviii-xxi,  May,  1906. 


34  THE   SUGAR-CAXE   INSECTS    OF    HAWAII. 

daily  be  distributing  thousands  of  natural  enemies,  that  should  control  these.  Al- 
though such  a  plan  or  modification  of  it  might  be  adopted  on  some  plantations,  on 
others  (at  least  such  as  are  under  irrigation)  it  would  either  be  difficult,  or  altogether 
impracticable.  Only  in  the  case  of  some  fields  of  long  ratoons  would  the  matter  be  very 
simple,  when  a  small  area  of  the  original  ratoon  growth  in  each  field  could  be  left  uncut, 
and  if  well  supplied  with  hoppers  and  their  natural  enemies  would  serve  later  on  to 
stock  the  rest  of  the  field.  Unfortunately,  owing  to  the  fact  that  ratoons  are  (except  in 
unusual  cases)  not  severely  attacked  as  compared  with  plant-cane,  this  matter  becomes 
one  of  minor  importance.  Otherwise,  in  the  majority  of  cases,  owing  to  the  clearing  of 
large  areas  and  the  burning  of  trash,  it  is  probable  that  new  fields  will  have  to  be  sup- 
plied by  cages  similar  to  those  already  used.  Two  things  will  be  absolutely  necessary: 
(1)  that  the  new  fields  be  well  supplied  with  parasites;  (2)  that  they  be  stocked  imme- 
diately the  hoppers  enter  them  and  commence  laying.  This  plan,  though  le>s  satisfac- 
tory than  would  be  the  other  method,  is  nevertheless  simple,  and  does  not  call  for 
much  expenditure  of  time,  nor  for  skilled  labor.  The  one  thing  necessary  to  be  posi- 
tively ascertained  is  that  the  spot  whence  the  cuttings  for  distribution  are  taken  is  well 
supplied  with  all  the  kinds  of  parasites  that  it  is  desired  to  establish  in  new  fields.  It 
is  now  well  known  to  us  that  all  these  destroyers  are  not  yet  established  in  all  parts  of 
all  plantations,  and  therefore  at  present  unless  an  entomologist  previously  test  samples 
from  the  spot,  whence  distribution  is  to  be  made,  it  is  quite  likely  that  some  of  the 
most  valuable  parasites  will  not  be  taken  to  the  new  fields.  If  a  sample  be  submitted 
to  the  entomologists,  it  can  be  passed  as  fit  to  supply  all  necessary  parasites  to  new 
fields,  or  if  not,  cages  of  the  deficient  species  can  always  be  supplied  from  the  cane  in 
the  grounds  of  the  Experiment  Station  in  Honolulu.  As  the  parasites  are  continually 
spreading  and  increasing,  such  expert  examination  will  at  the  most  be  necessary  for  a 
year  or  two;  for  it  is  perfectly  certain  that  by  that  time  all  the  species  will  be  so  gen- 
eral that  it  will  be  quite  impossible  to  take  any  extensive  sample  of  cane-leaves  that 
bear  egg?  of  leaf -hopper,  which  will  not  contain  all .  Such  in  fact  is  now  the  case  in  the 
cane  at  the  Experiment  Station.  To  sum  up,  the  clearing  of  all  cane  from  large  acre- 
age- is  a  decided  obstacle  to  the  complete  success  of  natural  enemies  of  leaf-hopper,  and 
the  burning  of  trash  aggravates  the  difficulty.  As  an  offset  to  these  conditions  new 
fields  should  be  supplied  artificially  with  natural  enemies,  and  they  should  be  supplied 
as  soon  as  any  leaf-hoppers  enter  them.  Of  course  future  observation  may  prove  this 
distribution  unnecessary,  but  for  the  present  it  should  be  adopted. 

RELATED    SPECIES. 

The  Hawaiian  sugar-cane  leafhopper  does  not  occur  on  the  mainland 
of  the  United  States.  The  insect  is  closely  related  to  the  corn  leaf- 
hopper  (Dicranotrojris  maidis  Ashm.),  common  on  corn  in  the  South- 
ern States. a  A  West  Indian  species  of  leafhopper  is  recorded  as  inju- 
rious to  sugar-cane,  by  Westwood,  in  1841,  under  the  name  Delphax 
saccharivora  and  is  a  member  of  the  same  family  of  insects  as  the 
Hawaiian  sugar-cane  and  the  corn  leafhoppers.6  Three  further  spe- 
cies of  this  same  family,  the  Fulgorida?,  are  recorded  as  sugar-cane 
pests  in  Java  by  W.  van  Deventer.c 


o  Quaintaxce,  A.  L.— Fla.  Agr.  Exp.  Sta.,  Bui.  45,  1898. 

b  Westwood,  J.  0.— Mag.  Nat.  Hist.,  vol.  6.  p.  407.  1841. 

c  Phenice  maculosa,  Dicranotropis  vastatrix,  and  Eumetopinn  hrugt  ri.  Van  Deventer, 
Handboek  ten  dienste  van  de  Suikerriet-cultuur  en  de  Rietsuiker-Fabricage  op  Java 
II.  De  Dierlijke  vijanden  van  het  Suikerriet  en  hunne  Parasieten.  Amsterdam, 
pp.  167-169,  1906. 


THE   HAWAIIAN    SUGAR-CANE   BORER.  35 

THE  HAWAIIAN  SUGAR-CANE  BORER. 

'  ([Sphenophorus]  Rhabdocnemis  obscurus  Boisd.) 
GEXERAL    CHARACTERISTICS. 

The  sue-ar-cane  "borer"  ([Sphenophorus]  Rhabdocnemis  obscurus 
Boisd.)  (fig.  4) ,  infesting  the  cane  stalk  in  Hawaii  is  the  grub  of  a  beetle 
belonging  to  the  weevil  family  Calandridae.  The  sugar-cane  stalk- 
borer  of   the  southern  United  States  is  the  caterpillar  of  a  moth, 


Fig.  4. — The  Hawaiian  sugar-cane  borer  ([Sphenophorus]  Rhabdocnemis  obscurus):  1,  Eggs,  natural  size. 
2,  Eggs  in  situ,  much  enlarged:  a,  Section  of  egg  passage  with  egg,  c;  b,  egg  placed  unusually  near  the 
rind,  d.  S,  Larvae,  just  hatched  and  older,  natural  size.  .1,  Full-grawn  larva,  natural  size.  5,  Larva, 
side  view,  enlarged :  a,  Spiracles;  b,  cervical  shield.  6,  Larva,  front  view,  enlarged.  7,  Pupa,  enlarged; 
a,  Rostrum  or  beak;  b,  antenna;  c,  elytron  or  wing  cover;  d,  folded  wing.  8,  Pupal  case  or  cocoon, 
enlarged.    9,  Adult,  enlarged.    (After  Terry.) 

Diatrsea  saccharalis  Fab.  Entomologically  the  two  species  are 
widely  separated,  belonging  to  entirely  different  orders  of  insects,  but 
in  the  character  of  their  injury  to  the  cane  stalk  these  two  insects 
are  quite  similar — that  is,  they  both  develop  within  the  cane  stalk,  and 


36  THE    SUGAR-CANE   INSECTS   OF    HAWAII. 

by  feeding  on  the  interior  cause  great  destruction  to  the  plant.  Com- 
paratively, the  Hawaiian  borer  is  more  destructive  and,  because  of  the 
habits  of  the  adult,  a  more  persistent  species  to  combat.  The  adult 
beetle  of  the  Hawaiian  borer  is  a  stronger  flyer  than  the  adult  moth 
of  the  mainland  borer  and  therefore  has  a  wider  range  over  anv 
infested  territory.  As  the  adult  of  the  Hawaiian  borer,  too,  can 
emerge  from  any  reasonable  depth  when  buried  in  the  soil,  this 
renders  the  question  of  infested  seed  cane  a  serious  one  in  Hawaii, 
while  on  the  mainland  the  careful  covering  of  infested  seed  cane  is 
effective  in  preventing  the  emergence  of  the  adult  moth.  These 
points  are  mentioned  to  bring  out  the  fact  that  we  are  discussing 
here  a  species  in  no  way  related  to  the  cane  borer  of  the  Southern 
States  and  in  many  ways  not  subject  to  the  same  means  of  control. 

[S phenophorus]  Metamasius  sericeus  Oliv.  is  a  species  injurious  to 
cane  in  the  West  Indies,  being  recorded  from  Jamaica,  Barbadoes, 
St.  Kitts,  Antigua,  St.  Lucia,  and  British  Guiana. 

In  Porto  Rico  S phenophorus  sexguttatus  Drury  is  recorded  by  Buscka 
as  boring  in  the  stalks  of  sugar  cane. 

DISTRIBUTION. 

The  sugar-cane  borer  of  Hawaii  is  recorded  also  from  Fiji,  Xew 
Guinea,  Xew  Ireland,  Tahiti,  Queensland,  and  the  Malay  Archipelago 
and  probably  occurs  pretty  generally  throughout  the  islands  of  the 
southern  Pacific. 

OCCURRENCE    IN    HAWAII. 

This  species  is  a  pest  of  long  standing  in  the  islands.  The  insect  is 
recorded  from  the  Island  of  Oahu  in  1885  by  the  Rev.  Thomas  Black- 
burn,6 who  found  the  species  breeding  in  the  stems  of  bananas  in  the 
mountains,  and  the  files  of  the  Bureau  (then  Division)  of  Entomology, 
record  the  receipt  of  the  borer  from  the  Hawaiian  Islands,  as  early  as 
1888.c  It  is  believed  that  the  sugar-cane  borer  was  introduced  into 
the  islands  from  Tahiti  in  the  stems  of  the  banana  plant  during  the 
early  communications  between  the  Hawaiian  Islands  and  those  of 
the  South  Seas.  Hon.  H.  P.  Baldwin,  of  Puunene,  Maui,  informed 
the  writer  that  to  his  personal  knowledge  the  beetle  was  injurious  to 
sugar  cane  in  the  vicinity  of  Lahaina,  the  ancient  capital  of  the 
islands,  as  early  as  1865. 

Aside  from  the  banana  plant  and  sugar  cane,  the  beetle  infests  the 
coconut  palm,  the  sago  palm,  the  royal  palm,  the  wine  palm,  (Cary- 
ota  urens),  and  the  papaia  (Carica  papaya). 

a  TJ.  S.  Dept.  Agr.,  Bur.  Ent.,  Bui.  22,  p.  89,  1900. 

&  Blackburn,  Rev.  T.,  and  Sharp,  D. — Memoirs  on  the  Coleoptera  of  the  Hawaiian 
Islands.     <Sci.  Trans.  Roy.  Dublin  Soc.,  2  ser.,  vol.  3,  pp.  119-290,  pi.  1,  1885. 
c  General  Notes,  Bureau  of  Entomology,  No.  4332b. 


THE    HAWAIIAN    SUGAR-CANE   BORER.  37 

Until  the  recent  injury  by  the  leaf  hopper  (PerMnsiella  saccJiaricida) 
the  sugar-cane  borer  was  the  principal  insect  affecting  cane  in  the 
islands. 

The  species  was  determined  by  the  Bureau  of  Entomology  at 
Washington,  D.  C,  in  1888  from  specimens  forwarded  by  the  late 
King  Kalakaua  and  was  discussed  under  the  title  "The  Sandwich- 
Island  Sugar-cane  Borer,"  in  Insect  Life,  vol  1,  No.  6,  pages  185-189, 
December,  1888. 

In  1896  Mr.  Koebele  gave  the  following  record  on  the  work  of 
the  borer  in  Hawaii :  a 

This  may  be  classed  as  the  most  injurious  enemy  of  the  sugar  cane  present  on  these 
islands.  Its  ravages  will  exceed  those  of  all  other  insects  combined.  Its  attacks  on 
the  sugar  cane,  however,  seem  confined  to  the  more  damp  localities,  whilst  in  drier 
places,  such  as  Lahaina,  the  borer  is  hardly  noticed.  I  have  been  informed  that  the 
Lihue  Plantation  has  recently  suffered  severely  from  the  attacks  of  the  borer.  Not 
only  sugar  cane  is  damaged  by  this  insect,  but  many  other  plants  are  damaged  by  it, 
chiefly  the  bananas  and  cocoanuts.  A  grove  of  the  latter  was  shown  me  in  Hilo,  in 
1894,  that  was  badly  infested  by  the  beetles.  Setting  fire  to  the  dry  leaves  was  rec- 
ommended; this  was  done  and  the  plants  have  since  entirely  recovered.  Dying 
cocoanut  palms  were  examined  and  in  the  tender  heart  of  the  palm  were  found  great 
numbers  of  the  insects,  in  all  stages. 

More  recently  (1907)  Mr.  F.  W.  Terry  lias  discussed  the  sugar-cane 
borer  in  the  Hawaiian  Islands  in  a  circular  of  the  Hawaiian  Sugar 
Planters'  Experiment  Station.6 

LIFE    HISTORY    A.ND    HABITS. 

The  eggs  are  found  beneath  the  epidermis  of  the  cane  stalk,  or 
more  rarely  in  the  tissue  of  the  leaf  sheath,  having  been  placed  singly 
in  small  cavities.  The  cavity  is  made  by  the  female  with  her  proboscis 
before  depositing  the  egg. 

The  young  grub  or  larva,  on  hatching  from  the  egg,  bores  on  into 
the  stalk  of  the  cane,  completely  honeycombing  the  interior  with 
tunnels  running  lengthwise  with  the  stalk  (see  fig.  5).  The  evidence 
of  its  work  is  not  indicated  by  the  outward  appearance  of  the  stalk. 
Many  times  a  stalk,  seemingly  in  a  normal  condition,  is  found  on 
examination  to  be  utterly  destroyed.  The  life  of  the  borer  within 
the  stalk  of  the  cane  is  estimated  to  be  about  seven  weeks  by  Mr. 
Koebele, c  who  points  out  the  fact  that  the  length  of  the  larval  life 

a  Koebele,  Albert. — Report  on  insect  pests.  <Hawaiian  Planters'  Monthly,  vol. 
15,  no.  12,  p.  590,  December,  1896. 

b  Terry,  F.  W  —  Hawaiian  Sugar  Planters'  Exp.  Sta.,  Div.  Ent.,  Cir.  3,  pp.  22, 
plates  2,  fig.  1,  December,  1907. 

c  Koebele,  Albert. — Hawaiian  Planters'  Monthly,  vol.  19,  no.  11,  p.  520, 
November,  1900. 


38 


THE    SUGAR-CANE   INSECTS   OF    HAWAII. 


I- 


Fig.  5.— Work  of  the  Hawaiian  sugar- 
cane borer  in  sugar  cane:  a,  a,  a,  Emer- 
gence holes  made  by  the  larva  before 
pupation;  6,  b,  "rupture"  holes,  ap- 
parently accidental  and  made  by  the 
larva  while  feeding;  c,  holes  made  by 
the  female  borer  for  the  reception  of 
her  eggs;  d,  cocoon;  e,  larva;  /,  /, 
"frass"  or  undigested  cane  fiber, 
passed  by  the  larva.  One-half  natural 
size.    (After  Terry.) 


depends  to  a  great  extent  upon  the  con- 
dition of  the  food  plant  and  climatic 
conditions;  that  is,  the  development  will 
be  more  rapid  in  softer  cane  and  during 
the  warm  summer  months  than  during  the 
low  temperatures  of  winter. 

When  ready  to  pupate— that  is,  to  trans- 
form to  the  inactive  stage  preparatory  to 
emerging  from  the  stalk  as  an  adult 
beetle — the  larva  (fig.  5,  a)  forms  about 
itself  a  cocoon  (fig.  5,  b)  from  the  fiber  of 
the  stalk  within  the  tunnels  it  has  made 
in  feeding.  The  adult  beetle  on  issuing 
from  this  cocoon  bores  its  way  through 
the  side  of  the  stalk  to  the  exterior,  and 
this  opening  in  the  lower  joints  of  the  cane 
is  the  first  distinct  symptom  of  the  pres- 
ence of  the  borer.  The  length  of  the 
pupal  period  is  as  variable  as  that  of  the 
larval,  the  average  time  for  transforma- 
tion and  emergence  being  from  two  to 
three  weeks. 

The  beetles  are  night  nving  and  hide 
during  the  day  down  within  the  sheaths 
of  the  lower  leaves.  The  softer  varieties 
of  cane  are  more  subject  to  attack  than 
the  hardier  varieties,  and  the  borer  is  more 
abundant  in  the  wet  districts  than  in  the 
dry.  Cane  which  has  received  an  abun- 
dant supply  of  water  by  irrigation  suffers 
more  from  the  work  of  the  borer  than  un- 
irrigated  cane.  The  borers  occur  in  the 
largest  numbers  in  young  cane  and  the 
suckers  are  infested  to  a  much  greater 
degree  than  the  stalks.  The  borers  always 
occur  in  the  largest  numbers  in  the  vicinity 
of  the  track  used  to  haul  cane  to  the  fac- 
tory, issuing  from  infested  stalks  that  have 
dropped  from  the  cars  and  have  not  been 
collected  and  destroyed  afterwards. 

The  borer  is  a  strong  flyer  and  spreads 
from  field  to  field  in  this  manner.  It  is  dis- 
tributed  in  infested  seed  cane  and  also 
develops  from  the  stalks  left  in  the  field 
after  harvest  or  dropped  from  the  wagons 
or  cars  in  hauling  to  the  factory. 


THE    HAWAIIAN    SUGAR-CANE    BORER.  39 

CONTROL  MEASURES. 

Selection  of  Varieties  for  Planting. 

As  has  been  mentioned,  the  softer  varieties  are  more  subject  to 
attack  than  the  hardier  ones.  The  Yellow  Caledonia,  a  variety 
which  is  replacing  to  a  great  extent  the  common  Lahaina  and  Rose 
Bamboo  in  Hawaii,  is  injured  to  a  much  less  extent  than  other 
varieties.  The  infestation  is  not  necessarily  less  in  Yellow  Caledonia, 
but  the  borer  meets  with  greater  resistance  in  its  feeding  and  conse- 
quent development  because  of  the  firmness  of  the  fiber. 

Irrigation. 

Excessive  irrigation  favors  the  development  of  the  pest,  since 
cane  in  a  succulent  condition  is  more  easily  infested  by  the  borer 
and  its  development  within  the  stalk  is  more  rapid.  It  is  plain  that 
in  fields  heavily  infested  by  the  borer  the  minimum  amount  of  water 
should  be  used  in  irrigation. 

Burning  of  Trash. 

The  burning  of  trash  after  harvesting  the  cane  is  the  most  effectual 
method  of  keeping  the  borer  in  check.  In  this  practice  not  only 
should  the  fields  be  burned  over,  but  all  the  unburned  stalks  left  in 
the  fields  and  all  stalks  dropped  from  carts  and  cars  along  the  roads 
and  tracks  used  in  hauling  the  cane  to  the  factory  should  be  collected 
and  burned.  One  plantation  found  it  necessary  to  collect  such 
stalks  in  piles  and  use  crude  oil  on  them  in  order  to  destroy  them 
completely,  and  by  a  careful  estimate  of  the  labor  and  cost  of  mate- 
rial found  that  the  money  had  been  well  invested,  as  was  shown  by 
the  reduction  in  the  numbers  of  borers  in  the  fields  the  following 
season. 

Selection  of  Noninfested  Seed  Cane. 

The  Hawaiian  sugar-cane  borer  is  able  to  emerge  to  the  surface 
from  any  reasonable  depth  when  planted  with  seed  cane.  For  this 
reason  great  care  should  be  exercised  in  the  selection  of  cane  for 
planting  purposes,  since  new  areas  can  in  this  way  be  readily  stocked 
with  the  pest.  It  is  not  practical  to  treat  successfully  cane  infested 
with  the  borer,  since  the  borer  is  fully  protected  within  the  stalk. 
Therefore,  next  in  importance  to  the  thorough  burning  of  all  trash 
after  harvest  is  the  selection  of  noninfested  seed  cane. 

Picking  and  Baiting. 

The  most  effective  direct  measure  employed  against  the  cane 
borer  is  the  collecting  of  the  adults  during  the  daytime  from  their 
hiding  place  within  the  lower  leaf  sheaths.     The  supply  of  labor  will 


40  THE    SUGAR-CANE   INSECTS   OF    HAWAII. 

influence  the  ability  to  use  this  method.  The  method  is  more  feasible 
where  the  plantation  is  so  situated  that  women  and  children  can  be 
employed  for  the  work.  Care  should  be  exercised  in  this  work  in 
order  that  the  growing  leaves  may  not  be  broken  down.  It  is 
obvious  that  a  larger  number  of  beetles  will  be  collected  when  the 
wages  are  based  on  the  numbers  collected,  but  the  results  are  more 
satisfactory,  as  regards  breaking  down  the  cane,  when  the  wages  of 
the  laborers  are  fixed  at  a  certain  amount  per  day. 

In  the  Fiji  Islands  a  method  of  baiting  the  beetles  is  employed, 
which  consists  of  splitting  cane  stalks  and  placing  pieces  about  the 
edges  of  the  field  and  within  the  rows  at  certain  intervals.  The 
method  as  practiced  in  Fiji  is  thus  described  by  Mr.  Koebele." 

At  the  request  of  the  Colonial  Sugar  Company  we  looked  into  the  matter  with  a 
view  of  getting  rid  of  the  beetles  the  best  way  possible;  all  sorts  of  devices  were  em- 
ployed and  none  worked  better  than  pieces  of  split  cane  about  12  inches  long,  placed 
along  the  edges  of  the  field  and  through  the  same  at  intervals  of  12-18  feet;  thus  with 
seven  little  Indian  girls,  I  collected  over  16,000  beetles  in  some  four  hours,  and  the 
same  little  girls  alone  brought  in  the  following  noon  over  20,000  beetles. 

This  method  was  kept  up,  and  followed  on  all  the  plantations  for  the  next  three 
years,  or  until  no  more  of  the  borers  could  be  found.  Tons  of  the  same  were  brought 
in  at  the  Nausori  mill  alone,  and  the  expenses  of  collecting  were  practically  nothing 
compared  to  the  cost  at  Lihue,  where  such  work  has  to  be  done  by  the  day  laborers. 
About  four  cents  per  pint  of  the  insects  was  paid  to  the  children.  The  result  has  been 
highly  satisfactory,  for,  ever  since  the  last  five  years,  the  cane  borer  has  not  been  a 
pest  in  those  islands. 

An  important  point  regarding  this  split  cane  is  that  the  females 
usually  infest  these  pieces  heavily  with  eggs  and  the  young  resulting 
grubs  bore  into  the  split  stalks  and  perish  as  the  pieces  of  cane  become 
dry.  In  dry  localities  the  pieces  of  split  cane  should  be  placed  in  the 
irrigation  ditches  during  the  day  and  placed  out  as  bait  in  the  even- 
ing, otherwise  they  dry  out  rapidly  and  cease  to  attract  the  beetles. 

RELATED  SPECIES. 

The  Hawaiian  sugar-cane  borer  is  represented  in  the  United  States 
by  the  "corn  bill-bugs,"  of  the  genus  Sphenophorus,  several  species 
of  which  in  the  adult  stage  attack  the  leaves  of  corn,  but  rarely  breed 
in  the  stalk  of  corn  as  does  the  Hawaiian  Sphenophorus  in  the  stalk 
of  cane.  The  Hawaiian  cane  borer  does  not  occur  on  the  mainland  of  the 
United  States. 

a  Koebele,  Albert. — Hawaiian  Planters'  Monthly,  vol.  19,  no.  11,  p.  522,  Novem- 
ber, 1900. 


THE    HAWAIIAN   SUGAR-CANE   LEAF-ROLLER.  41 

THE   HAWAIIAN    SUGAR-CANE    LEAF-ROLLER. 

(Omiodes  accepta  Butl.)     (Plate  III.) 

EARLY    HISTORY    IN    THE    HAWAIIAN    ISLANDS. 

During  the  investigations  relating  to  the  leaf  hopper  in  1903  the 
writer  found  the  Hawaiian  sugar-cane  leaf-roller,  the  caterpillar  of 
a  native  moth,  doing  serious  damage  to  cane  in  the  upper  fields  of 
plantations  in  the  Kohala  district,  Island  of  Hawaii.  The  larvae 
were  collected  also  from  Hilo  grass  (Paspalum  conjugation)  growing 
wild  above  the  cane  areas.  The  species,  primarily  a  grass  feeder, 
occurs  in  the  higher  altitudes  and  invades  the  bordering  fields  from 
these  locations.  It  is  recorded  by  Meyrick  a  in  1899  from  the  islands 
of  Hawaii,  Maui,  Molokai,  and  Kauai  at  elevations  ranging  from 
1,500  to  5,000  feet.  The  caterpillar  was  described  for  the  first  time 
by  Dr.  H.  G.  Dyar,  of  the  United  States  National  Museum,  from 
specimens  collected  by  the  writer  on  cane  in  the  Kohala  district. b 

Swezey  states  that  the  leaf-roller  occurs  on  practically  all  of  the 
plantations  of  the  islands,  but  is  less  abundant  in  the  dry  districts. 
Regarding  its  injury  he  says:c 

It  is  present  in  some  fields  of  cane  sometimes  in  such  large  numbers  as  to  do  consid- 
erable damage ;  in  fact,  cases  have  been  reported  where  the  young  cane  has  been  entirely 
stripped  of  leaves.  Such  instances  are  not  numerous,  however,  and  even  in  the  worst 
cases  would  not  result  in  entire  destruction  of  the  crop  of  cane  as  it  would  grow  again 
after  the  caterpillars  had  obtained  their  growth,  or  their  parasites  had  got  them  checked. 
It  is  not  usually  to  be  considered  a  serious  pest.  Possibly  it  is  not  so  abundant  now 
as  it  was  a  few  years  ago  when  reports  were  made  of  cane  fields  having  been  entirely 
stripped  by  them. 

At  present  there  are  a  number  of  parasites  preying  upon  this  species  and  this  keeps 
them  well  in  check. 

In  this  same  report,  page  10,  the  author  describes  the  habits  of  the 
caterpillar  as  follows: 

On  sugar  cane  the  very  young  larvae  feed  in  the  crown  of  the  plant  where  the  young 
leaves  have  not  yet  unrolled.  They  are  thus  protected  between  the  natural  rolls  of 
the  leaf;  later  on  they  roll  over  the  margin  of  a  leaf  forming  a  tube  for  their  "  retreat. " 
When  nearly  full  grown,  they  are  usually  found  in  tubes  towards  the  tip  of  the  upper 
leaves.  These  tubes  are  easily  observed  if  the  ragged  leaves  where  the  larvae  have 
fed,  are  examined.  The  work  of  the  smaller  larvae  shows  as  oval  or  elongate  dead 
spots  on  leaves  which  have  unrolled  in  the  growing  of  the  cane  after  the  young  larvae 
have  fed  upon  them. 

When  disturbed  in  its  retreat,  as  by  its  being  torn  open,  or  violently  shaken,  or 
jarred,  the  larva  wriggles  very  lively  and  drops  to  the  ground  for  escape.    This  habit  is 

°  Meyrick,  E. — Fauna  Hawaiiensis,  vol.  1,  Pt.  II,  p.  204,  1899. 

b  Dyar,  H.  G.— Note  on  the  larva  of  an  Hawaiian  pyralid  (Omiodes  accepta  Butler). 
<Proc.  Ent.  Soc.  Wash.,  vol.  6,  no.  2,  p.  65,  1904. 

c  Swezey,  Otto  H. — The  sugar-cane  leaf-roller,  Omiodes  accepta.  <  Hawaiian 
Sugar  Planters'  Exp.  Sta.,  Div.  Ent.,  Bui.  5,  p.  7,  August,  1907. 


42  THE    SUGAR-CANE   INSECTS   OF    HAWAII. 

probably  to  escape  from  parasites,  many  of  which  prey  upon  them.  The  retreat  which 
it  constructs  is  undoubtedly  for  the  same  purpose,  as  well  as  for  protection  from  wraps 
and  birds  which  prey  upon  it. 

The  caterpillars  are  full  grown  in  about  three  weeks  from  hatching.  They  molt 
five  times  at  intervals  of  about  three  to  five  days,  and  five  to  seven  days  between  the 
fifth  molt  and  the  spinning  of  the  cocoon  and  pupation.  Pupation  takes  place  wit  hin 
a  slight  cocoon  of  white  silk  in  the  "retreat"  where  the  caterpillar  has  lived;  how- 
ever, the  cocoon  is  sometimes  made  beneath  the  leaf-sheaths  of  cane,  and  in  other 
favorable  places. 

CONTROL  MEASURES. 

No  special  remedies  are  employed  in  cane  fields  against  this  pest. 
Swezey  suggests  that  in  fields  of  young  cane  a  spray  of  Paris  green 
or  arsenate  of  lead  might  be  used  with:  effect,  and  mentions  that  at 
times  laborers  have  been  sent  over  the  field  to  pinch  the  caterpillars 
in  their  retreat  between  the  folded  cane  leaves. 

PARASITES. 

The  species  is  attacked,  fortunately,  by  several  introduced  para- 
sites. Regarding  the  natural  enemies  of  the  species  of  moths  belong- 
ing to  the  genus  Omiodes,  Mr.  Swezey  reports  as  follows  on  pages  36 
and  37  in  his  article  above  referred  to: 

Omiodes  caterpillars  are  attacked  by  a  large  number  of  species  of  parasites,  some  of 
which  are  native,  and  several  which  are  the  most  valuable  have  been  introduced. 
The  most  of  the  species  are  kept  in. check  by  their  natural  enemies,  so  that  they  do 
not  become  very  numerous;  in  fact,  several  of  them  are  very  rare.  Two  species  feed 
so  numerously  on  cultivated  plants  that  they  become  serious  pests;  accepta  on  sugar 
cane,  and  blackburni  on  palms.  These  two  species  are  preyed  upon  very  extensively 
by  the  parasites  and  checked  considerably,  but  not  sufficiently  to  keep  them  from 
doing  considerable  injury  in  certain  localities  and  at  certain  seasons.  Apparently  the 
moths  are  more  prolific  in  the  winter  months  (about  December  to  March)  and  the 
parasites  are  scarcer  owing  to  their  having  had  fewer  caterpillars  for  them  to  keep 
breeding  on  during  the  preceding  summer.  Hence,  when  the  winter  broods  of  cater- 
pillars appear,  there  may  be  two  or  three  generations  of  them  before  the  parasites 
breed  up  to  sufficient  numbers  so  that  they  produce  any  noticeable  check  on  the 
number  of  the  caterpillars;  then  in  another  generation  or  two  the  caterpillars  may  be 
much  reduced  in  numbers  and  a  large  percentage  of  them  found  to  be  parasitized;  for 
example,  on  one  occasion  75  %  of  the  cane  leaf-rollers  in  a  field  at  Hutchinson  plan- 
tation, Hawaii,  were  found  to  be  destroyed  by  one  species  of  parasite;  at  Olaa  plan- 
tation, Hcwaii,  in  a  certain  field,  on  one  occasion  a  much  higher  percentage  of  them 
than  that  were  killed;  in  Honolulu,  of  a  large  number  of  the  palm  leaf-roller  cater- 
pillars collected,  90  %  were  parasitized. 

Since  there  are  so  many  species  of  parasites  preying  on  the  leaf-rollers  which  are 
pests,  it  might  be  asked  "Why  do  they  not  become  exterminated,  or  at  least  cease  to 
be  pests?"  Apparently,  with  all  of  the  parasites,  they  are  still  not  numerous  enough 
to  overbalance  the  prolificness  of  the  pest,  even  though  they  do  kill  such  high  per- 
centages of  them  at  times.  Since  so  many  are  killed  by  parasites,  and  yet  there  are 
enough  left  to  do  considerable  injury  at  times,  one  cannot  help  but  wonder  to  what 
extent  these  pests  might  increase  were  there  no  parasites  preying  on  them,  and  how 
many  times  more  serious  would  be  the  damage  done  by  them.  The  extreme  difficulty 
and  impracticability  of  treating  sugar  cane  fields,  or  large  palm  trees,  artificially,  for 


Bui.  93,  Bureau  of  Entomology,  U.  S.  Dept.  of  Agriculture 

ill 


Plate  III. 


The  Hawaiian  Sugar-Cane  Leaf-Roller  (Omiodes  accepta). 

Fig.  1.— Adult  moth.  Figs.  2,  3, 4, 5.— Larvae  and  details.  Fig.  6.— Pupa.  Fig.  7.— Apex  of  cremaster, 
showing  the  curled  spines  by  which  the  pupa  is  fastened  to  the  cocoon.  Fig.  8.— Cluster  of  4  eggs 
in  groove  on  surface  of  leaf.  Fig.  9.— Eggs  more  highly  enlarged.  Fig.  10.— Leaf  spun  together 
for  "retreat"  or  hiding  place  of  caterpillar;  showing  where  caterpillar  has  eaten.  Fig.  11. — Leaf, 
showing  spots  where  very  young  caterpillar  has  eaten,  leaving  one  epidermis  intact,  instead  of 
eating  holes  through  the  leaf.    (After  Swezey.) 


THE   SUGAR-CANE    MEALY-BUG.  43 

the  destruction  of  these  pests,  makes  it  all  the  more  important  that  there  are  so  many- 
valuable  parasites  preying  upon  them;  and  shows  the  value  of  introducing  natural 
enemies  to  control  a  pest,  for  the  four  best  parasites  of  these  leaf-rollers  are  introduced 
species,  viz.,  Macrodyctium  omiodivorum,  Chalcis  obscurata,  Frontina  archippivora  and 
Trichogramma  pretiosa. 

THE  SUGAR-CANE  MEALY-BUG. 

(Pseudococcus  calceolarise  Mask.)     (Plate  IV.) 

IDENTITY. 

This  insect  (see  PI.  IV,  from  photographs  by  Mr.  T.  C.  Barber)  is 
identical  with  the  sugar-cane  meaty-bug  common  on  cane  in  the 
southern  parishes  of  Louisiana.  The  species  is  recorded  by  Mrs. 
Maria  E.  Fernald  from  Australia,  Hawaii,  Fiji,  Jamaica,  and  Florida. a 
Koebele  earlier  records  this  mealy-bug  on  cane  in  Hawaii.5 

BELATED    SPECIES. 

The  mealy-bug  of  the  cane  belongs  to  a  very  large  family  of  insects, 
Coccidse,  which  are  world-wide  in  their  distribution.  Two  other 
species  of  this  family,  Pseudococcus  sacchari  Ckll.  and  Aspidiotus 
cyanophylli  Sign.,  have  recently  been  recorded  from  Hawaii  by  Mr. 
J.  Kotinsky.c 

Three  species,  namely,  Pseudococcus  calceolarise,  P.  sacchari,  and 
Aspidiotus  sacchari  Ckll.,  are  known  to  attack  sugar  cane  in  the 
West  Indies.^ 

Van  Deventer  records  several  scale  insects,  among  them  Lecanium 
hrugeri  Zehntn.,  Aspidiotus  saccharicaulis  Zehntn.,  Chionaspis  spp., 
and  a  species  of  Pseudococcus  very  similar  to  P.  calceolarise,  on  cane 
in  Java. e 

In  Mauritius  two  species  of  related  insects,  leery  a  seychellarum 
Westw.  and  Pulvinaria  iceryi  Guer.,  are  reported  as  pests  of  sugar 
cane/ 

FOOD    PLANTS. 

'Mrs.  Fernald  gives  the  food  plants  of  the  sugar-cane  mealy-bug 
as  Calceolaria,  Danthonia,  Phormium  tenax,  Cordyline  australis,  and 

«  Fernald,  Mrs.  Maria  E. — A  Catalogue  of  the  Coccidse  of  the  World.  <Bul.  88, 
Hatch  Exp.  Sta.,  Mass.  Agr.  Coll.,  p.  98,  1903. 

b  Koebele,  Albert. — Hawaiian  Planters'  Monthly,  vol.  15,  no.  12,  p.  596,  Decem- 
ber, 1896;  vol.  17,  no.  5,  p.  209,  May,  1898. 

cKotinsky,  Jacob. — Coccidse  not  hitherto  recorded  from  these  islands.  <Proc. 
Hawaiian  Ent.  Soc,  vol.  2,  no.  3,  pp.  127-131,  1910. 

d  Ballou,  H.  A. — Review  of  the  insect  pests  affecting  the  sugar  cane.  <West 
Indian  Bui.,  vol.  6,  no.  1,  p.  41,  1905. 

«  Deventer,  W.  van. — Handboek  ten  dienste  van  de  Suikerriet-cultuur  en  de 
Rietsuiker-Fabricage  op  Java.  II.  De  Dierlijke  vijanden  van  het  Suikerriet  en 
hunne  Parasieten,  Amsterdam,  pp.  227-266,  1906. 

/  Fernald,  Mrs.  Maria  E. — A  Catalogue  of  the  Coccidse  of  the  World.  <Hatch 
Exp.  Sta.  Mass.  Agr.  Coll.,  Bui.  88,  pp.  27,  133,  1903. 


44  THE   SUGAR-CANE  INSECTS  OF   HAWAII. 

sugar  cane.  In  Louisiana  the  mealy-bug  infests,  aside  from  sugar 
cane,  the  Johnson  grass  (Sorghum  Tialepense)  and  the  saccharine 
sorghums. 

LIFE    HISTORY    AND    HABITS. 

The  feeding  habits  of  the  mealy-bug  are  similar  to  those  of  the 
cane  leaf  hopper;  that  is,  their  mouthparts  are  formed  for  piercing 
the  epidermis  of  the  plant  and  sucking  the  plant  sap  from  the  inner 
tissues.  The  distinction  in  the  feeding  habit  is  that  the  leafhopper 
is  active  throughout  its  entire  life  cycle,  and  jumps  or  flies  from 
plant  to  plant,  while  the  mealy-bug  when  partly  grown  remains 
practically  stationary  and  feeds  upon  but  one  portion  of  the  same 
plant. 

Where  the  cane  mealy-bugs  occur  in  Hawaii,  they  can  be  found 
about  the  lower  leaves  of  the  cane,  congregating  for  the  most  part 
behind  the  older  leaves  near  the  ground.  The  species  may  be  recog- 
nized by  the  white  mearylike  covering  of  the  adult  female,  to  which 
the  common  name  applies.  The  insects  occur  in  a  mass  and  when 
abundant  are  readily  observable  by  the  white  covering  of  the  females. 
This  white  covering  serves  as  a  receptacle  for  the  eggs,  which,  upon 
close  examination,  may  be  observed  embedded  therein. 

In  Louisiana  the  insects  occur  not  only  about  the  lower  leaves  of 
the  plant,  but  are  to  be  found  also  around  the  crown  (Plate  IV,  fig.  1) 
and  beneath  the  surface  of  the  ground  about  the  roots  of  the  plant. 
In  this  latter  location  they  hibernate  during  the  cold  months  of 
winter  on  both  cane  and  Johnson  grass. 

The  young  mealy-bugs  upon  hatching  from  the  eggs  are  quite 
active  and  disperse  over  the  cane  plants,  finally  congregating  when 
partly  grown  about  the  lower  nodes  of  the  stalk.  The  females  are 
practically  inactive,  remaining  in  a  mass  about  one  of  the  nodes  or 
beneath  the  leaves  throughout  their  development  and  secreting  about 
themselves  in  these  locations  the  characteristic  white  covering 
(Plate  IV,  fig.  3).  The  young  males  do  not  remain  stationary  on 
the  plant,  but,  after  completing  their  development,  spin  a  narrow 
white  cocoon  (Plate  IV,  fig.  4)  within  which  they  transform  to  a 
delicate  winged  adult. 

CONTROL. 

Selection  of  seed  cane. — Since  the  common  method  of  distribution 
is  by  the  transportation  of  infested  seed  cane  from  plantation  to 
plantation  or  from  one  part  to  another  of  the  same  plantation,  care 
should  be  exercised  to  select  clean  stalks  and  not  those  which  are 
infested,  for  seed  cane. 

Burning  of  the  trash. — The  practice  of  burning  the  trash  after 
harvest  is  verv  effective  in  destroying  this  insect,  since  those  remain- 


Bui.  93,  Bureau  of  Entomology,  U.  S.  Dept.  of  Agriculture. 


Plate  IV. 


The  Sugar-Cane  Mealy-Buq  (Pseudococcus  calceolaria). 

Fig.  1. — Adult  mealy-bugs  clustered  about  the  base  of  young  cane.  Fig.  2.— Adult  female, 
twice  natural  size.  Fig.  3. — A  single  adult  female*  with  white  mealy-like  covering. 
Fig.  4.— Cocoons  of  male  mealy-bug.     (Original.) 


OTHER    SUGAR-CANE   INSECTS   IN    HAWAII.  45 

ing  on  the  stalks  are  killed  in  the  process  of  milling,  and  the  remaining 
forms  on  the  discarded  stalks  and  leaves  in  the  field  are  destroyed 
by  the  fire. 

NATURAL    ENEMIES. 

There  is  present  in  Hawaii  a  ladybird  beetle,  Cryptolsemus  mon- 
trouzieri  Mills.,  which  is  a  special  mealy-bug  feeder.  This  ladybird 
is  one  of  Mr.  Koebele's  introductions  from  Australia.  It  has  proved 
particularly  beneficial  in  feeding  upon  the  sugar-cane  mealy-bug 
in  the  Hawaiian  cane  fields,  and  through  its  work  the  numbers  of  the 
mealy-bug  have  been  greatly  reduced  in  recent  years.  This  impor- 
tant predator  has  been  established  in  California,  and  the  Bureau  of 
Entomology  at  Washington,  D.  C,  has  under  way  at  present  negotia- 
tions to  import  this  beetle  into  the  cane  fields  of  southern  Louisiana 
which  are  infested  by  the  mealy-bug. 

The  ladybird  is  thus  described  by  Prof.  W.  W.  Froggatt,  govern- 
ment entomologist  of  New  South  Wales.0 

This  beetle  is  very  variable  in  size,  measuring  from  under  2  to  3  lines  in  length, 
with  the  head,  thorax,  extreme  tip  of  both  wing  covers  light  orange-yellow;  the  whole 
of  the  under  surface  reddish-brown,  and  both  the  upper  and  under  surface  clothed 
with  fine  hairs.  In  a  number  of  specimens  the  under  surface  is  variable  in  colora- 
tion, the  middle  and  hind  pairs  of  legs  with  the  thorax  dark  reddish-brown  to  black. 

The  larva  is  of  the  usual  smoky-brown  tint,  but  so  thickly  clothed  on  the  upper 
surface  with  white  filaments  that  it  appears  to  be  of  a  uniform  white,  the  pupa  hidden 
beneath  the  larval  skin  and  the  immature  beetle  are  pale  yellow. 

MISCELLANEOUS  INSECTS  AFFECTING  SUGAR  CANE  IN  HAWAII. 

An  aphis,  Aphis  sacchari  Zehntn.,  is  occasionally  injurious  to  sugar 
cane.  Koebele  records  an  outbreak  of  the  species  on  the  Island  of 
Kauai  in  1896  under  the  name  Aphis  sp.6  The  species  was  deter- 
mined by  Kirkaldy  in  1907.c  This  insect  is  known  to  occur  on  cane 
in  Java,  In  Hawaii,  the  species  is  fed  upon  by  the  ladybird  Coccinella 
repanda  Thunb.,  though  the  benefit  from  this  beetle  is  offset  by  the 
work  of  its  braconid  parasite,  Centistes  americana  Riley. 

In  some  districts  where  the  cane  fields  are  situated  in  moist  loca- 
tions, a  mole  cricket,  Gryllotalpa  africana  Beau  v.,  is  sometimes 
abundant  enough  to  be  injurious.  Another  species  of  mole  cricket, 
Scapteriscus  didactylus  Latr.,  is  a  most  important  pest  of  sugar  cane 

«  Froggatt,  W.  W. — Australian  ladybird  beetles.  <Agr.  Gazette  of  New  South 
Wales,  vol.  13,  pt.  9,  pp.  907,  908,  September,  1902. 

b  Koebele,  Albert. — Hawaiian  Planters'  Monthly,  vol.  15;  no.  12,  pp.  596-598, 
December,  1896. 

c  Kirkaldy,  G.  W. — On  some  peregrine  Aphidae  in  Oahu.  <Proc.  Hawaiian  Ent. 
Soc.,  vol.  1,  pt.  3,  pp.  99,  100,  July,  1907. 


46  THE    SUGAR-CANE   INSECTS   OF    HAWAII. 

in  the  island  of  Porto  Rico.°     Regarding  the  work  of  the  Hawaiian 
mole  cricket,  Prof.  Koebele  reports  as  follows:6 

A  species  of  mole  cricket  has  appeared  in  very  large  numbers  in  some  of  the  moist 
valleys  on  Oahu,  it  is  likely  another  Asiatic  introduction,  as  a  rule  these  crickets 
are  found  around  the  muddy  borders  of  shallow  ponds  and  watercourses  where  they  live 
in  burrows  resembling  those  of  moles,  and  like  that  animal  their  food  consists  chiefly 
of  earth  worms  and  the  larva  of  various  insects.  The  opinions  as  to  its  habits  are  as 
yet  divided;  whilst  some  authorities  claim  that  it  is  beneficial,  others  place  it  amongst 
the  injurious  insects. 

Specimens  kept  in  confinement  here  with  pieces  of  sugar  cane  would  hardly  touch 
them,  yet  they  readily  devoured  a  large  number  of  the  larva  of  the  Adoretus  or  Japanese 
beetle,  as  well  as  those  aphodius  and  a  number  of  earth  worms,  all  within  24  hours. 

The  ground  infested  by  these  crickets  was  examined  and  found  to  be  very  wet  and 
completely  riddled  with  the  burrows  down  to  a  depth  of  three  and  even  four  feet,  as 
many  as  three  and  four  specimens  were  brought  to  light  in  a  single  shovel  full  of  the 
soil.  In  such  localities  there  is  no  question  as  to  the  injurious  effects  of  the  crickets 
on  young  cane  plants,  wherever  they  were  numerous  almost  all  of  the  seed  cane  was 
destroyed;  they  would  burrow  into  the  seed  from  all  sides,  destroying  all  the  eyes, 
where  the  plants  had  made  a  growth  of  a  couple  of  feet  the  cricket  would  burrow  in 
below  the  ground  and  eat  to  the  center,  killing  the  plant.  This  is  the  only  instance 
so  far  observed  of  the  depredations  of  these  crickets  here.  In  rice  and  taro  fields  no 
damage  has  been  observed  as  yet,  and  the  only  damage  that  is  likely  to  occur  to  cane 
is  when  it  is  planted  in  wet  swampy  land,  as  the  cricket  can  only  live  and  thrive  in 
such  places,  and  is  not  found  in  ordinary  arable  land;  even  in  the  swamp  where  the 
cricket  was  very  numerous,  it  did  not  attack  the  old  cane  but  paid  its  attention  solely 
to  the  newly  planted  seed  and  very  young  plants. 

This  cricket,  although  living  in  marshy  land,  cannot  live  under  water,  yet  it  is  a 
good  swimmer;  the  only  remedy  that  can  be  recommended  at  present  is  to  flood  the 
land  with  water  and  collect  the  crickets  as  they  come  to  the  surface,  destroying  them 
by  placing  them  in  a  vessel  containing  kerosene  and  water. 

The  fungoid  so  contagious  to  many  insects  and  larva  here,  does  not  seem  to  have  any 
effect  on  this  lively  cricket,  nor  will  he  have  anything  to  do  with  poison  given  in  the 
style  of  bran,  sugar  and  arsenic. 

Certain  army  worms  and  cutworms,  among  them  Heliophila  uni- 
puncta  Haw.,  Agrotis  i/psilon  Rott.,  and  Spodoptera  mauritia  Boisd., 
are  occasionally  known  to  strip  fields  of  young  cane.  These  species 
and  related  forms,  together  with  their  natural  enemies,  are  discussed 
in  a  recent  report  by  Mr.  O.  H.  Swezey. c 

A  bud  moth,  Ereunetis  flavistriata  Wlsm.,  is  found  generally 
throughout  the  Hawaiian  cane  fields  and  at  times  is  quite  numerous. 
Regarding  its  injury  Swezey  says:d 

a  Barrett,  O.  W. — The  changa  or  mole  cricket  in  Porto  Rico.  <Porto  Rico  Agr. 
Exp.  Sta.,  Bui.  2,  pp.  19,  fig.  1,  1902. 

&  Koebele,  Albert. — Hawaiian  Planters'  Monthly,  vol.  15,  no.  12,  pp.  594-596, 
December,  1896. 

c  Swezey,  O.  H. — Army  worms  and  cutworms  on  sugar  cane  in  the  Hawaiian 
Islands.  <Hawaiian  Sugar  Planters'  Exp.  Sta.,  Div.  Ent.,  Bui.  7,  pp.  32,  pis.  3, 
November,  1909. 

<* Swezey,  0.  H. — The  Hawaiian  sugar  cane  bud  moth  (Ereunetis  flavistriata) 
with  an  account  of  some  allied  species  and  natural  enemies .  ^Hawaiian  Sugar  Planters' 
Exp.  Sta.,  Div.  Ent.,  Bui.  6,  pp.  40,  pis.  4,  October,  1909. 


EATS    INJURING   SUGAR-CANE.  47 

It  is  usually  not  particularly  injurious  as  it  customarily  feeds  on  the  dead  and  drying 
tissues  of  the  leaf-sheaths  of  sugar  cane;  but  when  very  numerous  and  on  particularly 
soft  varieties  of  cane  the  caterpillars  do  considerable  eating  of  the  epidermis,  and  also 
eat  into  the  buds  and  destroy  them,  occasioning  a  good  deal  of  loss  where  the  cane  is 
desired  for  cuttings  to  plant. 

The  grasshoppers  Xiphidium  varipenne 'Swezey  and  Oxyavelox  Fab. 
feed  to  some  extent  on  the  leaves  of  cane.  The  former  species  is  also 
predatory  in  habit,  attacking  the  young  leafhoppers  and  the  larvae 
of  the  sugar-cane  leaf-roller. 

Two  species  of  beetles  which  occasionally  invade  the  cane  fields 
from  their  common  food  plants  and  attack  the  leaves  of  the  sugar 
cane  are  Fuller's  rose  beetle,  Aramigus  fuTleri  Horn,a  and  the  Japanese 
beetle,  Adoretus  taiuimacidaius  Waterh.6 

RATS  INJURING  GROWING  SUGAR   CANE  IN  HAWAII. 

The  so-called  roof -rat  (Mus  alfxandrinus)  in  former  years  was 
very  common  in  the  cane  fields  of  Hawaii  and  did  considerable 
damage  by  eating  the  stalks.  This  is  also  the  cane-field  rat  of  the 
island  of  Jamaica.  The  species  in  Hawaii  lives  now  for  the  most  part 
in  trees  and  the  upper  stories  of  dwellings,  since  it  has  been  driven 
to  a  great  degree  from  the  cane  fields  by  the  introduced  mongoose. 
The  introduction  of  the  mongoose  was  a  benefit  as  regards  its  destruc- 
tion to  the  rats  in  the  cane  fields,  but  the  animal  is  an  undesirable 
acquisition  to  the  fauna  of  the  islands  for  the  reason  that  in  recent 
years  it  has  included  in  its  dietary  the  eggs  and  young  of  ground- 
nesting  birds  and  domestic  fowls.  The  destruction  of  the  ground- 
nesting  birds  is  most  regrettable. 

«  Van  Dixe,  D.  L—  Hawaii  Exp.  Sta.,  Press  Bui.  14,  p.  5,  October,  1905. 
&Koebele,  Albert. — Hawaiian  Planters'  Monthly,  vol.  17,  no.  6,  pp.  260-264, 
June,  1898. 


NDEX 


Page. 

Adoretus  tenuimaculatus,  injurious  to  sugar  cane 47 

Adrastidia  nebulosa,  enemy  of  Perhinsiella  saccharicida 28 

Agrotis  ypsilon,  injurious  to  sugar  cane 46 

Algeroba .     (See  Prosopis  j u lifiora . ) 

Anagrus  columbi,  parasite  of  Perhinsiella  saccharicida 29 

frequens,  parasite  of  Perhinsiella  saccharicida 31 

parasite  of  Perhinsiella  vitiensis 30 

Anomalochrysa  sp.,  enemy  of  Perhinsiella  saccharicida 28 

Aphis  sacchari,  prey  of  Coccinella  repanda 45 

sugar-cane  pest  in  Hawaiian  Islands 11, 45 

sugar  cane.     (See  Aphis  sacchari.) 

Aramigus  fulleri,  injurious  to  sugar  cane 47 

Army  worms  injurious  to  sugar  cane 46 

Arsenate  of  lead  against  Hawaiian  sugar-cane  leaf-roller 42 

Aspidiotus  cyanophylli,  recorded  from  Hawaii 43 

saccharicaulis,  sugar-cane  pest  in  Java 43 

sacchari,  sugar-cane  pest  in  West  Indies 43 

Baiting  Hawaiian  sugar-cane  borer 39^0 

Banana,  food  plant  of  Rhabdocnemis  obscurus 36 

Beekeeping  in  Hawaiian  Islands,  relation  to  sugar-cane  leafhopper 20-22 

Beetle,  Japanese.     (See  Adoretus  tenuimaculatus.) 

Borer,  Hawaiian  sugar-cane.     (See  Rhabdocnemis  obscurus.) 

Bud  moth  of  sugar  cane.     (See  Ereunetis  fiavistriata.) 

Burning  against  Hawaiian  sugar-cane  borer 39 

sugar-cane  leafhopper 22,  23 

mealy-bug 44-45 

Calceolaria,  food  plant  of  Pseudococcus  calceolaria 43 

Cane-field  rat  of  Jamaica.     (See  Mus  alexandrinus.) 

Carica  papaya,  food  plant  of  Rhabdocnemis  obscurus 36 

Caryota  wrens,  food  plant  of  Rhabdocnemis  obscurus 36 

Caustic  soda  and  lime  against  sugar-cane  leafhopper 22 

lime,  and  copper  sulphate  against  sugar-cane  leafhopper 22 

Centistes  americana,  parasite  of  Coccinella  repanda 28, 45 

Chalcis  obscurata,  parasite  of  Omiodes  accepta  and  0.  blachburni 43 

Changa.     (See  Scapteriscus  didactylus.) 

Chelisoches  morio,  enemy  of  Perhinsiella  saccharicida 32 

Chionaspis  spp. ,  sugar-cane  pests  in  Java 43 

Chrysopa  microphya,  enemy  of  Perhinsiella  saccharicida 28 

Climate  of  Hawaiian  Islands 9 

Coccinella  repanda,  enemy  of  Aphis  sacchari 45 

Perhinsiella  saccharicida 28,  32 

host  of  Centistes  americana 28, 45 

Collection  by  nets  against  sugar-cane  leafhopper 22 

49 


50  THE   SUGAR-CANE   INSE4  IB   OF    HAWAII. 

Pa-- 

Copper  sulphate,  lime,  and  caustic  soda  against  sugar-cane  leafhopper 

Cordyline  australis.  food  plant  of  Pseudococcus  calceolaria 43 

Com,  food  plant  of  Dicrariotropis  maidis 34 

leafhopper.     i  See  Dicranotropis  maidis.) 

Crop  diversification  against  sugar-cane  leafhopper 26 

Crypto!  a  7n  us  montroicieri.  description 45 

enemy  of  Pseudococcus  calceolaria 45 

Cultural  methods  against  sugar-cane  leafhopper 25-26 

Cutting  and  burning  against  sugar-cane  leafhopper 22-23 

Cutworms  injurious  to  sugar  cane 46 

Danthonia.  food  plant  of  Pseudococcus  calceolaria 43 

Delphax  saccharic  ora  on  sugar  cane  in  West  Indies 34 

Diatraa  saccharalis.  sugar-cane  pest,  comparison  with  Rhabdocnemis  obscurus. .  .  35-36 

Dicranotropis  maidis  on  corn  in  Southern  States 34 

rastatrir.  sugar-cane  pest  in  Java 34 

Diseases  of  sugar  cane,  spread  by  PertinsieUa  saccharicida 19 

Diversification  of  crops  against  sugar-cane  leafhopper 26 

Ecthrodelphaxfairchildii.  parasite  of  PertinsieUa  saccharicida 2S,  29,  32 

Elenchus.  parasite  of  PertinsieUa  saccharicida 30 

Ereunetis  faxistriata.  injurious  to  sugar  cane 46-47 

Eumetopina  kriigeri.  sugar-cane  pest  in  Java 34 

Frontina  archippiiora.  parasite  of  Omiodes  accepta  and  0.  blackburni 43 

Fungous  diseases  of  leafhoppers  in  Hawaii 32-33 

enemy  of  Siphanta  acuta  and  PertinsieUa  saccharicida 28 

Grass.  Hilo.     (See  Paspalum  conjugation. 
Johnson.     (See  Sorghum  hale  per- 

Gryllotalpa  africana.  injurious  to  sugar  cane 45-46 

Hand  destruction  against  Hawaiian  sugar-cane  leaf-roller 42 

picking  against  Hawaiian  sugar-cane  borer 39-40 

Hawaiian  Islands,  climate  and  location 9 

sugar-cane  insects 11—17 

industry 9-10 

Heliophila  unipuncta.  injurious  to  sugar  cane 46 

Honeydew  honey  in  Hawaiian  Islands 21-22 

Hypochnus.   fungus  accompanying  injury  to  sugar  cane  by  PertinsieUa  sac- 
charicida    18 

Icerya  seychellarum.  sugar-cane  pest  in  Mauritius 43 

Insecticides  against  sugar-cane  leafhopper 22 

Insects  injuring  sugar  cane  in  Hawaiian  Islands 11—47 

Irrigation,  excessive,  favorable  to  Hawaiian  sugar-cane  borer 39 

ne  emulsion  against  sugar-cane  leafhopper 22 

Leafhopper,  corn.     (See  Dicranotropis  maio 

•    sugar-cane  (see  also  PertinsieUa  saccharicida). 

prey  of  Xiph.idiv.m  varipenne 47 

Leafhoppers  and  their  natural  enemies,  bibliographic  reference 29-34 

Leaf-roller,  Hawaiian  sugar-cane  (see  also  Omiodes  accepta  . 

preyed  upon  by  Xiphidium  varipenne 47 

palm.     (See  Omiodes  blacJ:burni.) 

Learn  iurn  trugeri,  sugar-cane  pest  in  Java 43 

Lime  and  caustic  soda  against  sugar-cane  leafhopper 22 

copper  sulphate,  and  caustic  soda  against  sugar-cane  leafhopper 22 

Macrodyctium  omiodiiorum,  parasite  of  Omiodes  accepta  and  0.  blackburni 43 

Mealy-bug,  sugar-cane.     (,See  Pseudococcus  calceolaria.) 


INDEX.  51 

Page. 

Melanconium  saechari,  control 27 

spread  by  Hawaiian  sugar-cane  borer 26-27 

PerJdnsiella  saccharicida 19,  26-27 

Metamasins  sericeus,  sugar-cane  pest  in  West  Indies 36 

Mole  cricket.     (See  Gryllotalpa  africona  and  Scapteriscus  didactylus.) 

Mongoose  in  Hawaii 47 

Mus  alexandrin  us',  injurious  to  sugar  cane 47 

Natural  enemies  of  injurious  insects,  importance  of  introduction  into  Hawaiian 

Islands 11-12 

CEchalia  griseus,  enemy  of  Perhinsiella  saccharicida 28 

Omiodes  accepta,  control  measures 42 

early  history  in  Hawaiian  Islands 41-42 

habits 41-42 

injury 41 

parasites 42^3 

sugar-cane  pest  in  Hawaiian  Islands 11, 19,  20,  41-43 

blacJcburni,  injurious  to  palms 42 

Ootetrastichus  beatus,  parasite  of  PerJdnsiella  saccharicida 31.  32 

vitiensis 30 

Palm,  coconut,  food  plant  of  Rhabdocnemis  obscurus 36 

leaf-roller.     (See  Omiodes  blackburni.) 

royal,  food  plant  of  Rhabdocnemis  obscurus 36 

sago,  food  plant  of  Rhabdocnemis  obscurus 36 

wine.     (See  Caryota  urens.) 

Palms,  food  plants  of  Omiodes  blackburni 42 

Papaia.     (See  Carica  papaya.) 

Paranagrus  optabilis,  parasite  of  Perhinsiella  saccharicida 31 

parasite  of  PerJdnsiella  vitiensis 30 

perforator,  parasite  of  PerJdnsiella  saccharicida 31 

Paraphelinus.  parasite  of  Xiphidium  varipenne 32 

Parasitic  enemies  of  injurious  insects,  importance  of  introduction  into  Hawaiian 

Islands 11-12 

Paris  green  against  Hawaiian  sugar-cane  leaf -roller 42 

Paspalum  conjugatum,  food  plant  of  Omiodes  accepta 41 

PerJdnsiella,  description  of  genus ' 13 

saccharicida,  appearance  in  Hawaiian  Islands 12-13 

control 22-2S 

description 13-14 

dispersion 14 

distribution 12 

factors  responsible  for  outbreak  of  1903 20 

fungous  disease 28 

habits 15-18 

injury,  extent 19 

to  cane,  character 18-19 

life  history 15-18 

natural  enemies 28-34 

related  species 34 

relation  to  beekeeping 20-22 

sugar-cane  pest  in  Hawaiian  Islands 11, 12-34 

vitiensis,  parasites 30 

Phenice  maculosa,  sugar-cane  pest  in  Java 34 

Phormium  tenax,  food  plant  of  Pseudococcus  calceolaria? 43 


52  THE    SUGAR-CANE   INSECTS    OF    HAWAII. 

Pineapple  disease  of  sugar  cane.     (See  Thielaviopsis  ethaceticus .)  page. 

Pipunculus  juvator,  parasite  of  Perkinsiella  saccharicida 32 

terryi,  parasite  of  Perkinsiella  saccharicida 32 

Platyomus  lividigaster,  enemy  of  Perkinsiella  saccharicida 28 

Predaceous   enemies   of  injurious  insects,   importance   of  introduction   into 

Hawaiian  Islands 11-12 

Prosopis  julijlora,  honey  plant  in  Hawaiian  Islands 21 

Pseudococcus  calceolaria :,  control 44-45 

food  plants 43-44 

habits 44 

identity 43 

life  history 44 

natural  enemies 45 

related  species 43 

sugar-cane  pest  in  Hawaiian  Islands 11,  43-45 

West  Indies 43 

sacchari,  recorded  from  Hawaii 43 

sugar-cane  pest  in  West  Indies 43 

sp.,  near  calceolarix,  sugar-cane  pest  in  Java 43 

Pulvinaria  iceryi,  sugar-cane  pest  in  Mauritius 43 

Rainfall  of  Hawaiian  Islands 9 

Rats  injuring  sugar  cane 47 

Rhabdocnemis  obscurus,  control  measures 39-40 

distribution 36 

food  plants 36 

general  characteristics 35-36 

habits 37-38 

life  history 37-38 

occurrence  in  Hawaii 36 

related  species 40 

sugar-cane  pest  in  Hawaiian  Islands 11,  19,  20,  35-40 

Rind  disease  of  sugar-cane.     (See  Melanconium  sacchari.) 

Roof-rat.     (See  Mus  alexandrinus .) 

Rose  beetle,  Fuller's.     (See  Aramigusfulleri.) 

Scapteriscus  didactylus,  injurious  to  sugar  cane 45-46 

Seed  cane,  noninfested,  selection  as  preventive  against  Hawaiian  sugar-cane 

borer 39 

sugar-cane    mealy- 
bug    44 

Siphanta  acuta,  attacked  by  fungous  disease 28 

Smut,  black,  of  sugar  cane,  accompanying  injury  by  Perkinsiella  saccharicida. .  18 

Soils  of  Hawaiian  Islands 9 

Sorghum  halepense,  food  plant  of  Pseudococcus  calceolarix 44 

Sphaeronema,  fungus  resembling  species  of  this  genus  accompanying  injury  by 

Perkinsiella  saccharicida  on  cane 18 

Sphenophorus  obscurus.     (See  Rhabdocnemis  obscurus.) 
sericeus.     (See  Metamasius  sericeus .) 

sexguttatus,  sugar-cane  pest  in  Porto  Rico 36 

Spodoptera  mauritia,  injurious  to  sugar  cane 46 

Stalk-borer,  sugar-cane.     (See  Diatrsea  saccharalis .) 

Stripping  leaves  against  sugar-cane  leafhopper 23 


INDEX.  53 

Sugar  cane  aphis.     (See  Aphis  sacchari.)  Page, 

borer,  Hawaiian.     (See  Rhabdocnemis  obscurus.) 
bud  moth.     (See  Ereunetis  flavistriata.) 

damage  by  Mus  alexandrinus 47 

diseases,  spread  by  Perkinsiella  saccharicida 19 

food  plant  of  Adoretus  tenuimaculatus 47 

Agrotis  ypsilon 46 

Aphis  sacchari 11,  45 

Aramigus  fulleri 47 

Aspidiotus  sacchari 43 

saccharicaulis 43 

Chionaspis  spp 43 

Delphax  saccharivora 34 

Diatrxa  saccharalis 36 

Dicranotropis  vastatrix 34 

Ereunetis  flavistriata 46^17 

Eumetopina  krilgeri 34 

Gryllotalpa  africana 45-46 

Heliophila  unipuncta 46 

Icerya  seychellarum -. 43 

Lecanium  krugeri 43 

Metamasius  sericeus 36 

Omiodes  accepta 11, 19,  20,  41-43 

Perkinsiella  saccharicida 11, 12-34 

Phenice  maculosa 34 

Pseudococcus  calceolarise 11,  43-45 

sacchari 43 

sp.,  near  calceolarise 43 

Pulvinaria  iceryi 43 

Rhabdocnemis  obscurus 11, 19,  20,  35^0 

Scapteriscus  didactylus 45-46 

Sphenophorus  sexguttatus • 36 

Spodoptera  mauritia 46 

insects  of  Hawaiian  Islands 11-47 

leafhopper  (see  also  Perkinsiella  saccharicida). 

preyed  upon  by  Xiphidium  varipenne 47 

Fijian.     (See  Perkinsiella  vitiensis.) 
leaf-roller,  Hawaiian  (see  also  Omiodes  accepta). 

preyed  upon  by  Xiphidium  varipenne 47 

mealy-bug.     (See  Pseudococcus  calceolarise .) 
pineapple  disease.     (See  Thielaviopsis  ethaceticus.) 
rind  disease.     (See  Melanconium  sacchari.) 
stalk-borer.     (See  Diatrxa  saccharalis.) 

Yellow  Caledonia,  resistant  to  leafhopper  attack 23-25 

sugar-cane  borer,  Hawaiian 39 

varieties  and' their  relative  resistance  to  leafhopper  attack 23-25 

least  injured  by  Hawaiian  sugar-cane  borer 39 

industry  in  Hawaiian  Islands 9-10 

Temperature  of  Hawaiian  Islands 9 

Tetragnatha  mandibulata,  enemy  of  Perkinsiella  saccharicida 28 

Thielaviopsis  ethaceticus,  spread  by  Perkinsiella  saccharicida 19 

Trap  bait  against  Hawaiian  sugar-cane  borer 39-40 


54  THE   SUGAR-CANE   INSECTS   OF    HAWAII. 

Page. 

Trichogramma  prctiosa,  parasite  of  Omiodes  accepta  and  0.  blackburni 43 

1  <  ran  in  singula,  enemy  of  Perkinsiella  saccharicida 32 

Xipkidmm  caripenne,  enemy  of  Perkinsiella  saccharicida 32 

sugar-cane    leafhopper    and    sugar-cane    leaf- 
roller 47 

host  of  Paraphelinus 32 

on  sugar  cane 17 

Zelus  pcregrinus,  enemy  of  Perkinsiella  saccharicida 28 


UNIVERSITY  OF  FLORIDA 


